Sorry, just got back from Christmas family-thing.
You said he is in less than a 1L tank? That is somewhere around .3g? I would recommend getting an inexpensive betta bowl (1g or 3L). That is my prefered minimum. It is hard to control ammonia in a tank under 2g. More do-able in a 1g+. Just a suggestion.
I would also recomend getting a thermometer so you can moniter his tempreture. I am trying to save my sister's betta because the water temp got too low (40*F!).
As far as his other issues, I don't know.