Suggest Treatment For Brain Tumor Leading To Seizures

A few months ago, my 17 year old nephew out of the blue had a seizure that lasted more than 30 minutes. Last week he passed out for no apparent reason. They have done MRI and CATSCAN and at first said he had a brain tumor. Then they said it was not but that there was something like it in his head but not in his brain. Now the doctor saw a brown spot in his blue eye that had been there since birth . He looked under his arm for another spot - which he found- and now is going to do more tests. What could it be?