Are these the symptoms of a tumour and if so where?

I have a friend who has for several years (he is ambiguous as to exactly how long) experienced headaches of varying severity. Since September last year he has begun to experience 'visions' of various events, both while awake and sleeping.

The content of these visions tends to involve his own topics of interest with a heavy spiritual focus. He experiences weeks of bliss, tingling, involuntary convulsions, and feelings of closeness to God and disassociation from normal activity, usually aggravated by meditation and yoga.

These are intersped with days of severe, crippling headaches and irritability. Overall, his personality is shifting towards more paranoid and emotional reactions to events. He has not sought medical help as he is convinced he is moving towards Nirvana and that doctors will 'think he's crazy' and medicate him.

He fears this due to a history of being overmedicated during his teen years for minor allergies by his mother, which caused depression and suicidal thoughts.

Is it likely he has a brain tumour, and if so, what should I urge him to do?

(A bullet-point list of symptoms is in the tags)