Sleep Apnea Treatment

I have two-year-old twin boys, who I love to pieces. My eldest boy, William, has recently had a lot of medical problems with his ears (diagnosed completely deaf in his left ear, caused by glue ears) and also had reoccurring tonsillitis. He is on a waiting list to have an operation, which will have grommets inserted into both ears as well as a tube inserted into his Eustachian tube, plus his tonsils & and adenoids are going to be removed. Plus he also has Obstructive Sleep Apnea.
Now William has a real problem when it comes to bed. They both have slept all night since 3 months, but now William wakes up screaming (and I mean the scream like he is petrified or in extreme pain). He gets into these angry rages and will thrash about until he is allowed out into the lounge room. We have been really firm with him, and constantly taking him back to bed.
He has now started hurting himself. I know, he is only 2 how can he hurt himself. He bites himself, has drew blood and left numerous bruises over himself. Also he head butts the walls, and pulls his hair out. I am really scared; he is such a lovely happy boy until bedtime comes.
I just really want him to stop hurting himself. I have been crying all day over it. He won’t listen to neither Andrew and I. I know I should take him to the doctor: I do have an appointment Friday.
Please does any one have any advise how to stop these fits he is having. He is so aggressive and him hurting himself scares me. Any advise????