Hair loss on cat

Hello all. I'm new here but need some help with our male 6 year old tabby cat. Fred is losing his hair (fur) on his hind end for a few months now. Took him to the vet once and said it was caused by dry skin. He sedated him and gave him a protein bath! His day at the kitty spa cost me $100! It worked for a while but now it's coming back. I can't afford to continue to do this! LOL! It's only on his hind quarters. Rear legs and tummy are almost bald! There is nothing else wrong with him. Anyone know of any homeopathic or over the counter remedies I could try? Thanks!

 

is he licking it off or is it simply falling out?
Licking could be stress related (any changes at home?) or allergies - or fleas.
Allergies could be diet related.
What do you feed him?
If dry only check for corn - that is a big culprit for cats since they are carnivores and corn isn't a normal part of their diet but some cat food companies use it as filler (it's cheap).
Read the labels on the food and do a google search on dry cat foods/quality - you'll find tons of info online about cat food and various ingredients.