Wantmorepeace.
I relate to your mentioning that you are going through the stages of grief.  I feel the same. It makes sense that we are. You are making changes and feeling more of your feelings now that you have room to. They seem to pop up uninvited don't they? I have more compassion for pwbpd as theirs are so very intense. My only advice is to be gentle with yourself as you are with others. You are healing and I feel like good self care moves things along better than pushing and pulling at ourselves to be in a different place. I'm saying that for myself because I too want to feel better and do better. I am not always so accepting of my struggles.  All I know is, you have encouraged me. I think you are on a good path.

Well stated.  One day, greeting a pwBPD with a "How are you?" could elicit a negative reaction, and they might scream, Stop asking me how I am!  It's none of your business!  I don't want to talk about it!  You have no idea how horrible my life is!  A week later, they could complain that you never ask about them and don't seem to care.  You can't "win".  As Wantmorepeace explained, it's not really about what you say, it's all about your son's extreme mood in that particular moment.  He just hasn't learned yet how to react in a "conventional" way.  He could say, "It's not a good time to speak right now, would you mind if I called you later (when I am calm and not distracted)?"  But he's not there yet.

I see lots of progress here.  On the one hand, you're more accepting of your son as he is.  On the other, you're learning how to adjust your expectations and temper your own emotional responses.  But most of all, your son seems to be making progress in handling his emotions while under stress.  The reduction in suicidal talk, the avoidance of self-destructive meltdowns, his muddling through daily stresses without blaming you or demanding you to fix his problems--that's tangible progress in my opinion.  He's learning to set some healthy boundaries for his own benefit:  he's saying he doesn't want to talk about certain things, or he'll become overwhelmed and might say or do something he regrets.  That's progress in my opinion.

Now I know it's hard to feel like you're being censored, that you're not really allowed to express yourself freely, and that everything seems to revolve around your son's needs instead of yours, but that's where you are at the moment.  Nevertheless, there seem to be times when your son is more relaxed, upbeat, even loving.  I'd say, enjoy those as much as possible.  It sounds to me like the momentum is moving in a positive direction for both of you, and that's fantastic.  As you know, BPD is really tough to deal with, and change is hard, so it can help to think in terms of baby steps.  Even so, these seem like major steps forward to me.  Let's be cautiously optimistic that the progress continues for you both.

After rereading all your posts, I thought more about interacting with boundaries.  Don't have expectations about a call. Take each as they come understanding that I didn't cause or create a reaction. Especially when I keep my words kind and light.
Don't take reactions personally. Enjoy the light moments and know the heavier ones eventually pass.

That's a great update!  Hopefully things continue on the right path.

Update : my husband and I started marriage counseling.  I wanted to make sure we in a good place to do it. So far my husband has been doing his own work and he started a low dose mood stabilizer. Coupled with all his hard work, he reports to me it has really helped.  He can really pause before reacting.  I think his therapeutic work gave him great tools and the med is making things more effective for him.

I did not want to do therapy to just discuss arguments.  One thing that was important to me was that I needed to feel consistently safe around him.  Where at a good place to work how to understand and express our feelings.  For my husband I need him to not speak in a threatening matter.  I need him to trust that he will be heard when he speaks with respect.  He has been more vulnerable lately and I have been able to listen better because I not is a fright and flight response to accusations and yelling.  I asked him how he he felt after expressing himself (in a good way) telling me something he was upset about.i asked if he felt heard.  He said he did and he seemed at peace and not emotionally abusive or isolating.  I always wanted him to learn  to resolve conflict in a good way.  I think we are at a good start for counseling.

I am hopeful. I'll keep you posted

Thank you - each one of you. I know you all get how important it is to have people/ friends who understand.  You all are that to me. I think for me anyway, denial can take a lot of time to clear. For all these years I would think if the problem was solved, the condition would be right he'd be fine and blossom. I read and I experience over and over that he doesn't think or process the way I do or his brother or cousins do. I'm choosing to accept the superficial contact as the best that we can have and enjoy his laugh or him asking questions. .  It beats the rants, melt down , suicidal talk. As was said, he doesn't have the bandwidth. My T says his bucket is full - he doesn't have room for anything else.
Also, more clarity is changing the way I see how to best support my son. Hands off and caring from the sidelines. Now to be strong and clear during the storms. Also I do agree sometimes it feels right one time to say something and the same comment another time would ignite a blast furnace.  Trial and error for sure.

The driving under the influence is a concern, but I emphasized these statements too. Your D is afraid of her BPD mother being angry and abusive. These stood out to me because, I felt this way too.

I don't have legal information for how to proceed. I think it is worth talking to your attorney about what to do, if there's anything possible. If your D is old enough to have a voice, expressing her feelings is in her favor. Even without the evidence of drunk driving- she's afraid.

I don't know how much you can do without evidence, however, your D has a voice- she can speak up to her counselor about it, and also how to protect her from backlash, because her mother will likely react if she thinks she said something. But her feeling fearful of saying anything is significant- she's afraid to stand up for herself because of the consequences.

PS

In the meantime, you tell your daughter that her safety comes first, no matter what.  If your daughter suspects that a driver is drunk, she shouldn't get in the car in the first place.  If she has a cellphone, she should call for help--you, another adult, 911.  If she doesn't have a cellphone, then she should find another adult/teacher/friend-with-a-phone and ask them for help.  You can frame it in terms of your daughter's safety, not about her mom or stepdad. 

Hi,

One sign that your daughter is telling the truth is that her mom swore her to secrecy!

One thing your daughter might do is approach a school counselor and express her concerns about her mother and stepdad driving drunk, because it puts her in harm's way.  That might impel the counselor to report, which might trigger a CPS investigation.

I don't know to what extent gathering evidence yourself would be admissable in court, but my recommendation would be to try to photograph your ex's car for damage (discreetly of course), and possibly the mailbox.  You know the mantra here--document, document, document.  Even if the "evidence" doesn't reach the courtroom, I think it might help substantiate a case, such as with CPS.  My sister did that sort of thing with her ex, who was an unsafe driver and got into accidents, some like the one you describe.  Ultimately, her kids' concerns about smaller accidents, near-misses and getting lost on familiar routes were enough for courts to remove their dad's ability to drive the kids anywhere.  I'm pretty sure it all started when one of the kids approached a school counselor about this.

If your ex is anything like my disordered uNPD family member, she will have a spotty driving record.  The police might have a file on her.  In other words, one report of a small accident with no police intervention or evidence might be disregarded.  But if you can establish a pattern and reason for ongoing concern, then you might get something done about it.  One standard approach would be to require a breathalyzer test whenever your daughter is driven by her mom, to ensure your daughter's safety.