R.L.
I agree with the tough love advice. I have experience with a bi polar dad and a severe ADHD- borderline personality disorder sister. I can tell you from experience until they hit their own rock bottom and realize they need help, they will not accept any and they will only keep taking and taking. If they are not on meds or in counseling, they should be, but believe me I know they probably don't think they have any problems and just want to play the poor me card and wallow in their disorder. Of course then there is the natural rebellious reaction of who do you think you are, I'm fin I don't need any help etc etc. I know how frustrating it can be!
Good news, my dad has been off meds for several years now and is living a productive life manic free!! My sister is also doing well, she has grown out of a lot of her issues. Although she still has some extreme emotions she can deal with them a lot better now! She is a great mom and her and I have become closer!
So my advice is don't try to be their friend, they will thank you for it later! I know how hard it is to watch someone you love make mistakes and mess up, but unfortunately they are adults and some people just have to learn things the hard way. Just keep loving them but don't let them walk all over you!
Hang in there, it won't last forever!