Do you stay in the relationship or jump ship at this point?

I have this friend and she has been dating this guy for almost a year. The guy is basically falling apart. He eats a bowl of icecream everyday, is overweight, is depressed, has suicidal thoughts, and slacks off a lot. This friend has been giving them advice to help them, but in almost a year she could only help change him being high all the time. This friend still loves him, but is so tired of carrying the relationship. She feels that if she told him, his fragile ego would break and he'd kill himself. Recently, she has been talking to a girl to be a roomate, but they have been getting closer. The two girls kissed. Neither the future roommate or boyfriend knows about the other's relationship yet. My friend doesn't know whether or not to stop with the girl and be honest, see where it goes and keep quiet, break up and see where it goes with the girl, just stop either, or what. She likes the girl, but she doesn't know if it's the girl or not having to take care of the other person and validate them. What do you guys think?
Personally, I believe that her relationship won't last that long with that boy in the first place. He is all of the place and unstable. It will end, I just don't know when. I have never met the girl, but my friend is someone who seeks stability. I have no idea where it would or could go with the girl. I need your help to get a better perspective on the situation.
Do you stay in the relationship or jump ship at this point?
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