I've worked in some unhealthy, dysfunctional environments. It's just like a dysfunctional relationship, in that it doesn't matter how much YOU try to make it better, if they're not doing anything to make it better.

In both the jobs and the relationships, I'd keep trying, but it would always end badly.

It is best to leave an unhealthy job, if you can. Sounds like you have a good support system that would enable you to look for a decent job where there is a more healthy environment.

If you can do it, then leaving is definitely the best thing to do. Good luck.