Again, not trying to be a jerk but you are not a vet and doing home diagnosis is not going to help you or the snake. It will probably end with the snake dead. You need to just take him into the vet and get a real diagnosis, not guess work. Just be aware though, unless the root problem for the illness is fixed, all the medicine in the world wont help. You seem to know more than any of us about the care the snake needs so asking us just seems like a set up for an argument.
Bottom line is the snake needs a vet and his cage needs some serious modifications since a snake in the proper environment are generally very hardy. They get illness from a compromised immune system which is caused by stress, incorrect husbandry or a combination of both. But like I said, you seem to try and contradict any info we give you and say we are all wrong. If that is the case, why ask us? At least you do agree he needs a vet. I wish you the best of luck with that guy but judging by all the problems you have posted he has, he is going to have a serious uphill battle. Good Luck.