Will my bala shark be okay?

Hi. I have a bala shark that I've had for about 9 months. Well on Sunday I changed the decor and the gravel in my 56 gallon tank and put all of my fish into a big container. I would rinse some of the gravel and when I put it into the tank I would check the fish to make sure they were okay. When I came back to check on them(maybe 5 minutes or so) my poor bala was on the floor..I freaked out and my husband came and put him back into the water. He sat for a second then swam a bit but mostly just sat at the bottom of the container I'm sure out of shock. Within a day I noticed his eyes becoming white and hazy and his breathing had slowed down. I put melafix into the tank and added some extra salt to calm him and get his protective coating back. We got the hospital tank set up and ready for him and he's been in there swimming around like normal but now he seems to be resting. The poor guy has lost half of his back fins and he can't see which means he can't eat. I feel so bad for him he's already been through so much. He had hemmorogic septicemia and the other fish tore his fins up so bad he couldn't swim..but we fixed him right up and he had never been better. So I'm pretty upset that he has to go though this. Sorry I'm rambling on and on I just don't know what else to do for him...the water perimeters in both tanks are great and my other fish are doing fantastic. But my bala was one of my first fish. Can anyone tell me if he will be able to see again and how long it will take for his tail fins to grow back? If he will ever be able to eat again. Oh and also if there may have been brain damage..he was out of the water for probably about 5 minutes. Thank you so much in advance for any suggestions and please no mean comments I already feel pretty horrible as it is.