papilledema

My 11 year old son went for an eye exam friday.  They found swollen never endings and sent him to an opthomologist (spell wrong I am sure).  He said he had pseudotumor cerebri and ordered a CT scan that came out normal other then swollen optic nerves in both eyes at 7mm and 8mm(3 X the normal size).  He is to have a Lumbar Puncture today and the opthomolosist is certain in will come out fine with a high opening pressure. and a visual field test next week.  My son is normal height but weights 247 and is morbitly obese.  The opthomologist said if he losses the weight the problem will recover.  But our primary physican we went to(who doesn't know much about PTC) said he may need a shunt.  Who is right and should we see a neurologist for this too.
Also in the last 6 weeks he went from 235 to 247.  Could that weight gain have caused this?