Is your brother interested in nutrition?
My opinion is that your chances are so much better with combination of meds and nutrition. My father had a kidney transplant 13 years ago so he was on immunosuppresants which means that he battled GBM with little or no immune system. He lasted almost 2 years with GBM, all good until the last 1-2 months.
You may or may not have heard of Dr Jeanne Wallace she is a PHD in nutrition and specializes in cancer patients. She is great and her approach makes sense. We went with her because another member referred her to me at the time. She is full of knowledge and she is well woth the money. You pay about $350 for her initial report after you send her all the information and then if you want to talk to her, she charges per the time spent with her on the phone. I rarely called, I only purchased the sopplements she recommended and that is it.
Everyone has a nutritional wonder cure for cancer out there. If you want to save time researching and if you want an expert at brain tumors give her a try. Google the name or write back and I will give you her info.
Good luck
Joe