Hi Hizzy,
Welcome to the BPD Family
I like you joined this group by discovering BPD in relation to my significant others' (SO's) undiagnosed BPD ex-wife (uBPDxw). She too has been diagnosed as Bipolar but in my (very unprofessional) opinion the BPD shoe is a better fit.
I have recently purchased and began reading the book 'stop walking on eggshells: taking your life back when someone you care about has borderline personality disorder.' And, I am now aware of this website and hoping to get support from others who are experiencing similar things.
I'm glad you've found us! This is a great place to get support, learn tools and strategies that can help with your interactions with your mom.
Your mom's drinking is sad, her falling and hurting herself is sad, but you can't fix it for her even though you'd like to. She has to recognize she has a problem and she has to seek help. Not you, not your dad, not anyone else can fix her drinking problem, only she can take this on. I was married to an alcoholic for 20 years... .I tried and I tried, and I supported, and I supported, and I threatened and I threatened.
Then I acted. I divorced my husban, gained primary custody of our son, he had his 3rd DUI, lost his retirement (used to pay for attorneys), went to work smelling of alcohol, lost his job... .he hit rock bottom. It took loosing everything for him to finally get it and seek help. He has been sober for the last 5 years.
The lesson I learned was we can only change ourselves, we can't do it for anyone else.
I've not been in contact w/her since and have read a lot about going 'no contact' and think how this could really benefit me.
No contact (NC) is one way to go, but there are others... .there is NC forever, there is NC for awhile (while you take a break to learn more or while you take a break to re-charge for example), there is Low Contact (LC) (see her less often or communicating via email for example), there is learning some of the tools here that can improve your interactions with your mom... .boundaries, don't JADE (Justify, Argue, Defend, Explain), validation, improved communication skills. Or any combination of above.
Other than getting a nasty letter on my door when I got home from work last Wednesday I've not heard from her. In years past I would have reacted to the letter and called her up and argued. I've since learned that this is a waste of my energy, time and sanity.
This was a good reaction (non-reaction) on your part. You used one of our tools... .you did not JADE. When we JADE we feed the drama and can just spend our time and energy spinning in a circular argument, by not reacting/engaging, you absolutely saved time and energy.

Below are links to more information on JADE & Circular Arguments... .
https://bpdfamily.com/message_board/index.php?topic=139972.0https://bpdfamily.com/message_board/index.php?topic=92025.0https://bpdfamily.com/message_board/index.php?topic=118892.0Again, Welcome!
Panda39