Help, please

I desperately need some help with getting my son to have a haircut, I have tried keeping him up all night until he falls into an exhausted sleep, holding him down and doing it as quickly as we can, distractions, and tonight we tried, under doctors supervision, sedation. Nothing works. It takes 3 strong adult men to hold him down and we have to stop several times because it feels as if he will have a fit or something. He gets so incredibly distressed it is unbearable to watch or put him through. He had an MRI recently and we begged the doctor to allow us to cut his hair then, with no luck.

He cannot stand the clippers or the scissors, he had 3 and a half times the adult dosage tonight of a sedative, and that didn't work made him a little sleepy. He ends up making really low gutteral sounds, and can't even talk in the end, it is far too hard for him to cope with.

We have tried desensitising him to haircuts, by talking about it, taking him with us to hairdressers, cutting our own hair at home so he can help, even holding scissors/clippers near his head without cutting his hair. We can comb and wash his hair with no problems, cut his fingernails with little hassle, just not cut his hair.

We honestly feel that he either thinks we are cutting him, or it actually hurts him to have the hair cut. He cannot handle the hair falling on his face or neck, and claws at it, the last time leaving scars all over his face from his fingernails.

I am at a real loss, and am starting to get desperate, as he has very thick red hair that grows very fast, and makes his head very hot. He has a condition also, which means he is unable to sweat on one side of his body and overheats really easily. If it wasnt for that I wouldnt care that much how long his hair is, but because of this, we need to keep it as short as possible.

I welcome any suggestions at all, please

Thanks, Robyn