Although I don't agree with everything Jordan Peterson says about everything, he has a wise take on this:

https://www.youtube.com/watch?v=JzkXZAD_cT8

"If someone who is sinking has their hands around your neck and is pulling you down, you are not obligated to drown with them".

Sure, if someone wants to be helped, and you are able to help them without sacrificing your own health, you can do so. But don't sacrifice your own health for someone who is unable to help themselves.

I have learned this lesson the hard way several times. One of those times was devestating, when I was in an intmate relationship with someone with paranoid schizophrenia. I tried desperately to save them over the course of 10 months, but it wasn't enough, and it nearly destroyed me in the process.