Swim bladder Betta fish

I have a two tail, royal blue betta fish. When I first had him(him, he is a male), he was always very active, and would move around the cage all crazy like.

Any way, it technically is my baby sister's fish, and I was caring for it, but sister wanted to feed it. So mom moved it to the baby's room. It got less attention there, but had plenty of ambient light. Anyway, mom moved it to the hallway again, when the baby lost interest, and now she feeds him.

But recently he has been not moving, his fins are clamped, and he lies on his side all day. Tonight I took the lid off and put a few pellets in, and he tried to go get them, but he didn't seem to be able to move away from the side of the cage. I decided the closest thing to his symptoms is swim bladder disease, and here is my evidence for it:

1. the day before we noticed it, mom was doing a full change of his water, when he jumped out and on to the counter, and squiggled around for a second or two. mom quickly put him in small tank, but he did get jiggled.
2. he does try to move, but it seems difficult.
3. he spends most of the time at the top of the tank on his side.

It might not be swim bladder disease because:

• he lies on his side, but not vertically as described online. (sorry, no links for my rep level:P...)

If my diagnosis is correct, I would like to know what I should do to make him more comfortable. please explain your diagnosis.