What Causes Constant Pain, Weight Loss And Weakness In Legs?

My son sleeps 18 hours a day at least for two and a half years neurologist, hematology, internal medicine have turned up nothing is in constant pain has lost 65 lbs with no lose of appetite his legs give out and he falls down, he was perfectly fine before he fell 2 1/2 years ago, seeing an endrocologist next possibly infectious disease the chronic care integrated services say his problems are far beyond there scope of expertise, his muscles in his legs and hand twitch, which he is now video taping,when he is in pain his blood sugars will soar To 33.5 the highest the meter reads and when the pain subsides it drops to normal check him immediately after his falls and always in normal range any suggestions?