My brother's betta fish is severly ill!!!!?

I have 12 years of betta fish knowledge on my shoulders but I don't know what is with my brother's betta fish... He has had it for over a year now. He keeps it in a small, plastic betta tank(about 4" by 8"). We checked on it Saturday afternoon and it was sitting at the bottom of the tank breathing funny. I moved it to the bathroom to put it under observation, then it was put in a tiny plastic cup for further attendance. No, we haven't taken his fish to the vet because that is a little rediculous but i'm starting to feel bad for that fish. He has been ill since Sat, and its Thurs, so... its been almost a week! He is suffering. I want to know what is atleast wrong with him and why he hasn't died yet. His chest is VERY bloated and he looks like a bubble about to pop. His bloated chest is sort of whitish, unusual from his normally bright red scales. He just lays on the bottom of the plastic cup, breathing heavily. Occasionally he will weakly, wriggle his way to the top of the cup to resurface then sinks back to the bottom. In the clear cup he is in there is brown dusty looking stuff sitting at the bottom. What the heck is it?! Please post your comments!