Discipline is knowing what you can control and what you cant control. Make a list. Know the facts even if they aren't willing to accept them. Work from there.

On another note, I'm gonna say that the most discipline thing you can do in a toxic house is move out, or become homeless, Because peace is priceless at the end of the day, it's what your willing to sacrifice. Unless your obligated or required by law to stay in this toxic environment of course by all means ,build discipline. Having people you can't trust or people you think might put you in harms way given the opportunity ,is like putting your whole life in jeopardy though. It's others that will often make you feel like you need to pay for peace, and that is simply not the case.