My Grandson Has Been Told He Has Swollen Optic Nerves

My grandson has been told he has swollen optic nerves and that is the cause of his headaches. His vision has also gone from 20/20 to now needing glasses and vision is now needing a plus 8 prescription but his eyes can't take this and they have him in 3.25 for now. He also complines of leg pain a lot. I also noticed that he just doesn't have the energy a 6 year old should have and if he does much activity his face turns almost purple and sweats a lot. Do you think they are right in that they say he has pseudotumor cerebri or could it be something else and maybe with his heart?