Extreme Fatigue post shunt surgeries

I have a 21 year old son who had a first ever seizure and it was discovered he had hydrocephalus. The doctors assume he had hydrocephalus for a while as his ventricles were large and had high pressure in order to push the C CSF through the blockage.  They did a third ventricularostomy but he got meningitis right after the surgery.  Had it for three weeks before it was treated.  After he recovered from that, all was well.   Eight months later he had excrutiating headaches and vomiting.  Turned out he needed a shunt as the previous surgery was no longer working.  Because he is a 6"1 kid around 200 lbs and because he has big ventricles, they played around a litlte with the setting and set the Codman shunt at 180.  I know this is  high, but even at 160 he was a little light headed.  He is away at college and every time we talked to him, he was always sleepy.  For first time ever his grades were lower and he had gained a lot of weight  (240ish).  In addition, the pressure before the shunt was put in pressed his optic nerve and he has double vision.  We are waiting to see if it self corrects (within 6 mos) We are seeing a neurological opthomlogist.  Five months after the shunt was put in, he started sleeping inordinate amounts, 20 hours, up for 2 down for another 16 or 20.  This went on for a few days.  Finally we got to the ER and the shunt had misfunctioned.  The promimal (front end) of the shunt had "sucked in" some choroid plexuses and was replaced.  They kept the shunt at 180.  Still has double vision.   Now he is sleeping a whole lot again and continues to yawn when he is up.  He has been exercising, eating very healthy and losing a little weight.  We went to the ER and the shunt is working fine and they said the blood work indicated his thyroid was fine.  The incredible fatigue seems to have started with the shunt.  Has anyone else had this problem?   I am so concerned and would appreciate any ideas, input, suggestions.

Thank you.