Dying Betta

Question
I think my beta may be dying, is there anything I can do? My little sister dumped a whole bunch of food into his tank last night, but i didn't find out until this morning, and now one of the beta's eyes is MEGA swollen, and he's not swimming around very much. He just sits at the bottom of the tank and doesn't move. Please tell me if there's anything I can do to help him!!!

Answer
Hi Melina,
Change all of the Betta's water, and refill his tank with water of the same temperature he is in now, using a good water conditioner such as Stress Coat.  Treat him with Maracyn, and Maracyn-two combined.
I hope the little man pulls through.
Lynda