Family doesn't respect my dietary options, what to do?

Hi, long time lurker but never posted anything! Some background:

Currently in a program to go to a psych hospital everyday to get my shit together. This means I don't work, can barely take care of myself (barely shower once every two days), and so cooking is still too much for me.

So I (23) live with my divorced parents (51F, 50M), though what matters here is my dad and brother (18M). I've recently changed my diet to no red meat (middle ground to future vegetarian), and while my mom was ok, my dad just kinda refuses to make an effort. He takes us (me and my brother) to restaurants with no options for me, at home he also doesn't make options for me, and when I ask about it he acts like I'm crazy for asking, and that I shouldn't be so uptight and stop them from eating what they want.

Last time I talked to him about the restaurant part, he said it's about us being together, not the food, and so I shouldn't make a big deal out of it. Right after that, he started talking with my brother about a ribs only restaurant he was going to take us in the future.

Is there anything I can do?

TL;DR: Dad and brother disrespect my diet daily, too mentally ill to just cook for myself, what can I do?