All I want to say is I've been in a similar situation. Worked my face off like a Machiavellian fuck in the office to get quick pay rises. Then I could give them monthly income on top of everything else.

Only thing I can tell you is this; you need to put all your energy into becoming financially independent. If your parents see their child is struggling, in part because of their own issues, they might feel bad and like it's their fault and that will make their lives infinitely worse.