Suicide attempt

I want to get a large spectrum of opinions without asking something like Facebook where everyone knows my family's business. 
My sister is beautiful, she's insanely talented and makes me laugh like no other. She's adopted and she was diagnosed with being bipolar and having ADHD. She has always been difficult to live why but we try the best we can to give her all that she needs. She's attempted suicide three times now. She's currently on a 72 hour hold at a local psych ward. She only wants to go home and has told everyone under the moon that she wants to get better. But this is the third time and my mom and I can't let this keep happening. My sister has more power over my mom than my mom does over my sister. My mom is also a pushover and that doesn't help either. We are not sure how to help her or make it any more safe in the home. We have everything locked up but she still gets drugs and things to hurt herself with. 
She was also recently diagnosed with being psychotic. We are out if options and we would love all of your help and opinions. Thank you!