Need adult child advice.....badly!! (long)

Sorry....this is really long! Short version of history....daughter adopted at age 10.5 from Guatemala. Find out years later she was horribly sexually abused by birth family. Went through 6 years of counseling...to no avail because she didn't want help. She ran away at age 18 and now has twin boys that are 10 months old. She is in a program for homeless, single moms run by the Volunteers of America. She is dating a felon. Baby's dad is involved with the boys and is a seemingly a good dad. This is my struggle.....she is obviously borderline personality. She has every characteristic on the list. She lies about everything. Tells me she can do whatever she wants with her life (which is true) BUT is constantly having me watch the boys for days and never has any money so asks me for things like tampons and toilet paper. I buy all the things the boys need including formula because she always runs out. Her boyfriend steals from her and uses her DSHS debit card so she never has any food. She is in jeopardy of losing custody of her boys (which might be a good thing) but has a freeby lawyer so constantly files bogus complaints about the baby's dad etc... SO...I don't know how to interact with her. If I confront her she's mad. If I don't jump in to help she lets the boys go without or leaves them with her crappy friends. It's never enough to call CPS but not good situations. I feel like I'm enabling her, but if I don't do things for her she will make sure I don't see the boys. I've been the only constant in the boys' lives. I feel trapped and manipulated but do I just suck it up for the boys' sake?