99% Sure My Rescue Baby is Blind

[LumiZoomi]

Hello all! Around May/June, I got three rescue hams from a pet store that was closing. None of the pet store owners knew anything about them (sex, age, breed, NOTHING). So of course, we took them home and started to love them. I sexed them, as did my mom, and we decided they were all males. After a lot of research, I decided that they were most likely hybrid hamsters.
Over this summer, two of the three of them died spontaneously. No signs of illness or strange behavior. They'd be fine one minute, I'd go get a snack and come back, and they would be dead.
The last one left is our Bubbas. He was the smallest of the three, and the one with the most problems. He was a bar-biter, he would fall off the platforms in his habitat, he wouldn't sleep in his igloo or chew on his toys. He became very aggressive when I tried to tame him, nipping at me and even making squealing/clicking noises. My mother has gotten bit-hard-quite a few times as well.
Recently, my mom took over care of him, but he's gotten worse. When she goes to feed him, he doesn't see her moving her hand into his habitat, and he freaks out. We've tried to get him some new toys, but he doesn't seem to see them...or anything.
I've moved him into a 10-gallon "hospital cage" until we see some sort of improvement, but he's still acting strange. He doesn't use his wheel at all, but he runs around the walls of the tank all day and night. He is eating and drinking as normal, but doesn't use an igloo.
He definitely isn't deaf, but we're almost certain that he's blind.

To make it all worse, there is not a small-animal-friendly vet ANYWHERE near me, so I can't get him checked out.

We don't want to put him down, but I don't want him to be miserable.

Thoughts?

[CMB]

Try a different house. Igloos are kind of see through so are light inside. Hamsters need a dark nest are. Igloos can get hot and condensation forms from the hamsters breathing.

A cardboard box open at the bottom with a hole cut in can make a nice dark house or you can buy a house. Make sure it is big enough for your hamster, some nesting tissue and a food hoard. If it's bigger a toilet in the house may be needed if the hamster pees in the house.

A blind hamster will navigate the cage by smell and memory, so don't move anything in the cage. Talking to your hamster will let it know you are near and be less startling. You may have add food etc whilst the hamster is asleep so it isn't stressed by suddenly finding/smelling your hand in the cage.