Hi Webzy
Sorry I repeat, this is a bit rambly!
My son returned home at 24, just before Xmas and it was just awful. I got to work on the forum and realised that I finally had to either just let him go (homelessness) or try something I'd never tried before. Afterall, everything I'd ever done just made things worse. I saw that I had to change my approach.
At first, I pushed. I had a non-functioning adult living at home and I wasn't going to financially support him forever. I tried to get him to find work. I tried to get him to sign on for benefits. I tried to get him to get through an interview. I tried to get him to the GP to get signed off as sick if he couldn't function. I tried to get him into some sort of mental health treatment. All failed. I learnt my lesson - I'm a slow learner

It took years!
We were happy to provide bed and board for the time being. It couldn't go on forever though could it. At the very end of the day, we have our own lives and plans for retirement etc - also a younger son to consider. I tell you it was scary, my husband has fearful as I was. I did not like my son, hated his behaviour, hated his illness, he'd lie, cheat, steal from us - but he was obviously very depressed and in a lot of pain. Our house was just so sad. We were in an emotional mess.
What on earth were we to do? Allow him to remain in this inert state?
This sounds simple and I realise you may not believe me but here goes.
It was a three-pronged approach. I got myself a plan, I stopped giving him money, I left him to work out his own problems.
My personal three goals:
1. Improve my core relationship with my son24
2. Get him some financial management skills
3. Get him to live independently at some point (no timescale set)
I took a long time to work them out. I considered more but if I could achieve these 3 I'd be happy forever. Amazingly I didn't add stop drugs and get therapy - my reasoning being that these were his choices and he'd have to be self-motivated for these to work. I figured that even if, for whatever reason, my son left our home then No 1 was needed for all our sakes.
I see your situation is different as your daughter is living independently with you paying. Now I posted and asked for advice - maybe you want to do the same. Some said, get yourself a contract, one said they were reducing financial payments in phases. Posting up and asking direct questions is great - you can then pick and choose as you want, choose to do something else. All our situations are unique. It's important to be comfortable and trust your gut. I encourage you to talk to you husband, really take some time discussing and then reflecting on what
your long term goals are. You may be happy to financial support her forever, your priorities most probably are different than mine; our lives are different.
How to improve my core relationship? Well, first of all I stopped judging or criticising him. I'd go further with this, I got light as a fairy whenever he was around. Real smiley and cheerful. He'd come into the kitchen for a few minutes and I'd say "hi". I'd leave the silence awhile, see if he'd start a conversation, and if not then I'd talk about anything, anything but problems. Weather, funny story, bit of family news, what I was cooking - anything and everything unimportant.
I stopped questions. I stopped judging or criticising. I didn't ask him to do anything. I didn't talk about his problems. I made every interaction count.
Slowly, and I mean slowly, he started to seek me out or start a conversation with me. I treated each conversation like a gift. I'd try my new skills I was quietly learning on the forum. Validating, validating, validating.
He started to warm up, relax around us. He knew that he was "safe". He started to open up. This is when I needed to use those skills I'd been quietly learning. It didn't come easy as I found validation hard to sound natural. SET & DEARMAN came later when I started to tighten the screw down a little when I moved onto step number 2.
It took him 3-4 weeks to find himself his first day's work. I offered to drive him there and back.
That was a breakthrough.
I tried to not sweat the small stuff.  :)isgusting room etc. It wasn't my priority.
I had one boundary - no drugs or smoking in the house. My son was a quiet BPD and didn't rage but internalise his feelings. Limits I set, I kept flexible to meet wherever he was at at that time. He faced challenges he'd never faced before and I'd allow him the space to work out his problems himself. Little things like opening up a debt collection letter (another breakthrough that he opened it). I couldn't believe it when he actually called them up. He's never paid it back by the way.
My son is now 27. He works outside doing a job that he can manage. He enjoys it, has thrived and is now taking on responsibilities there. He struggles with relationships with his two bosses but they like him and understand him (some) so I think it's working out OK. His living arrangements are not ideal but he'll work this out eventually. He stays in touch, regularly comes to eat (particularly when he's hungry and he has no money). He's reduced his drugs by 80% as it was financially unsustainable. Moving out (my idea) was a push, timed right because I knew he was ready. We cracked open a bottle of champagne - we just couldn't believe it.
I'd be really interested to hear your thoughts. I feel this forum has saved my family. I fully committed to our core relationship and it was the BEST thing I've ever done. My family is closer, happer - despite the problems (because they are still there).
I used to give my son options. I used to set an expectation. I stopped doing it. I let him work out how he could help himself. Everything that he should do himself, he should do himself. I realise now that for him to behave like an adult, he needed to be treated like one - gently, supportively. We all want to feel loved and be understood. Getting the balance right is a tricky thing - but it can be done and I hope that you have some hope.
What's your husband say?
Hugs
LP