Help

Okay I need help, I went to petsmart for some cat litter but ended up seeing this pitiful betta and I really couldn’t walk away. I have multiple tanks at my place and got this hospital tank set up for him. I’m no expert but I’m pretty sure it’s swim bladder, could be wrong someone give me some advice! He lays on his side and isn’t able to move much. Currently got him in shallow water since he’s not swimming to the top for air. And I’ve got his water temp at 78. Not really sure what else to do