I'm pulling for you and your little guy, too! Warm water, AQ salt, and positive thoughts are the best you can do for your betta right now. But I'm sure you could use a hug. Or a punching bag.
I don't blame you for wanting to get away from those guys. I wouldn't trust anyone who mistreats animals.
Also, welcome to the forum!
ETA: Could your roommate be talking about a gourami? They are closely related to bettas and have many similar requirements such as not being with other gourami or betta, but they do need larger tanks. I don't mean to sound like I am defending the scum bag; I'm just trying to figure it out for the health of your fish.