How do I get my autistic son to stop whining?

He is 11 years old for Chris' sake!! He will be entering middle school in August, and I don't want him beaten up, shunned, made fun of, or embarrassed. When he gets frustrated he whines and complains. He has done this ever since he was a little boy. I understand he is autistic and I usually place him in the "Helen Keller" category, but I need to try!! What should I do?? Usually, if the family gets fed up with him, we banish him to his bedroom. We can't stuff socks in his mouth (I think this is abuse??) but what else can I do? We need him to stop this nonsense before we end up taking him to family orientation this August!! So I need answers.... NOW!