
Welcome to BPDFamily, happy to meet you, sorry you're here...
It's relatively common for BPDs to not accept the diagnosis, more common than Bipolars I think - and the major reason would likely be their overwhelming feelings of shame. Coupled with their lack of identity, and being told they're BPD they think that's an identity and an awful one at that...so they flee from it. Sadly the substance abuse is also remarkably common in both BPD and Bipolar, as I'm sure you're well aware.
One thought regarding the not working is seeing if she's amenable to applying for social assistance and therefore at least having some form of income rather than simply making demands solely off family. Her "job" for this month could be figuring out how to get some welfare dollars incoming so she's spending "her own money" on these vices and mistakes.
Regarding the suicide threats, it's always a good-news, bad-news issue for newcomers. The good news is that the vast, vast majority of the time no matter how loud their cries for help it will not result in anything permanent. The bad news of course, is that it only takes one "mistake" where they cut too deep or calculate the pills incorrectly or somehow manage to tie a knot correctly for once, for the unthinkable to happen - and pwBPDs do still have the highest rate of suicide attempts whereas Haltlose-without-BPD (uncommon) I think is the highest rate because they seek out less dramatic but more lethal means.
I saw somebody recently on these forums discussing how we caretakers start to feel guilty as we take their suicide attemptss less seriously. A professional not versed in BPD refused to believe me that I really couldn't say how many attempts I've witnessed or heard her reference...but honestly, I know it's more than six and fewer than sixty...beyond that, it's more difficult to count. The other user, a mother I think, was talking about how when her pwBPD said "Well that's it, I'm going to kill myself later tonight!" or something similar, her response had simply been a droll "Shall I call 9-1-1 now or do you want me to wait until later?". Callous, hurtful and yet completely excusable...possibly even helpful.
PS: I'm guessing from your username that I'm not alone in having watched an episode of the new LiS and thinking "Whoa, they don't say it aloud but there's a walking BPD case!". Never saw the old one, but the new one...yeah, definite "pseudo-PTSD" to seeing such a BPD character so accurately portrayed.