Yeah he doesn't look too bad in the stomach region. I think at least for his short life he was happy and comfortable, and very much loved - better than dying in a tiny little cup :)
I've got his tank covered with a blanket to keep it dark to minimize stress. I peek under the corner every so often to check on him and the light startles him and he jerks but then goes back to laying on his back. Just a waiting game now I think :(
I try to be optimistic, so on the plus side: I can go get the betta that's been haunting me at Petco for the past 3 weeks and not feel guilty about it :) Thanks for your responses!