When you say "lesions", do you mean metastases? My brother had a whole bunch of little ones, too many for Gamma Knife-type procedures, so he had 10 days of whole-brain. He was death walking, or rather shuffling, for a week, then he got better, and then he started losing feeling in his left hand and the left side of his face. After three days his daughter noticed and forced him to the emergency room. They did a CT scan and said he was having some seizure activity, probably due to the dosage of steroids that went with the radiation being too low, or decreased too fast or too soon. He didn't recognize his symptoms as seizures. Right now he's in the hospital for observation and treatment of the neurological issues. They still say he should recover from the radiation in 4-6 weeks.
He seems kind of afraid to leave the hospital, but that may be because he has no experience with neurological cooties. He looks way better than he did during the chemo, but he thinks he's sicker. Gamma rays sound scary.
My brother is in the process of retiring from his teaching job, which I think is part of the problem. When you have a profession that requires cognitive functionality, especially if you're a man, you feel like you've become a waste of space. Me, I retired on disability first from the Army and then from word processing pools in investment banks; I took up spinning and knitting and Barbies and haven't been this content since... ever. I don't know what to advise my brother to do as we live in the city and he can't garden or anything like that.
Does Tarceva affect the appetite or cause nausea? Do the doctors say the radiation arrested the progress of the disease? Maybe he just needs to recover from the radiation sickness -- after all, it's the same as what you see in the science fiction movies. And for sure he'll have to accept some loss of mental facility, but maybe there's an interest he can pursue that will occupy him.
I wish you the best; this stuff is a bear, ain't it?
--jayne