6 year old in induced coma for over 20 days seizures all tests negative - frustrating experience

Hi all, I am new here. My cousin's son is 6 years old and he is in the Children's hospital of Philadelphia. He had fever (103), stomach ache and head ache for 3 days and then the day after thanks giving in the early morning hours he had a seizure in his sleep. Parents found out at about 7am. He was air lifted to the hospital. Dr. think that some virus got into his brain. He was getting sever seizures. He was given all kinds of med to control the seizures. Initially seizures were coming from the right side of the brain (90% of it). MRI showed brain damage and Dr. don't know if that is due to virus or seizures. All known virus and bacteria tests came negative. So Dr. still don't know what it is and if it is gone. Seizures might be an effect of the damage caused by virus or bacteria. Dr. consider brain surgery to remove the seizure point in the right side of the brain. Suddenly they noticed that seizures were coming from all over the brain and so surgery idea was dropped. They started reducing Pentabarbetol from 6.5 down to 1. He was seizure free for about 30-40 hours but then started again. They eventually removed pentabarbetol but couldn't remove isoprofen completely. He is at 1.2 level on that. Dr. Also did bowel movement as the stomach was becoming BIG and hard. Now about 20 days have passed but Dr. couldn't control the seizures and the child is still unconcious. Dr. wants to try Ketonic diet now or called ketogenic I think. I couldn't find any such type of pediatric seizure + induced coma case so far on the net. If any parents have gone through similar (close not necessarily exact) experience then please share with us. It would provide some comfort and also what to expect going forward. Thank you in advance. -Neil