yes, pedialyte is safe for cats. and at this point, I would be forcing fluids moreso than forcing food. I'm no vet, but I do know that when cats avoid food and water in defense of medical conditions, it's not at all uncommon for them to suffer UTIs, even kidney failure. cats are very prone to UTIs, and they get bad, even deadly, fast.
oh, and on the food situation, DON'T switch brands on him right now, that will only make matters worse. If he's on dry food, you can try softening it with warm water or mashing it up, but stick to whatever he's eating right now. if you don't think he's getting enough calories and nutrition, there's a gel that comes in a tube that most pet food stores carry, it's used for hunting dogs and it's high calorie. when my kitty was knocking on death's door with a kidney infection, the vet told us to smudge a little on her nose every now and then throughout the day, I could tell that it did give her more energy.
as for getting him to the vet, getting him to one is the best idea, but I understand that's not always a possibility, as I can't afford a vet bill right now either.
but it never hurts to make some calls and do a little homework. Most bigger cities have a Humane society branch, or you could just start calling any vet and explain your situation and ask if they know of anyone in town who works with low-income clients.
Another route you could take is to find out who in your area fosters rescue animals, and see if you can get ahold of them. My neighbors take leftover cats from adoption events and adopt them out from their home, now granted they have waaaaay too many cats at their house, they've been just as resourceful for my cat as any vet would, and they did it for free. most of the time it's the vet-techs from a clinic who take orphaned animals home, and they often have extra anti-biotics, etc.
I don't know, I'm just trying to help you getting the wheels turning on getting him taken care of without having a huge vet bill. good luck! hope he gets better
