If your BIL has brain mets, he is stage IV, which is not good. But it is treatable and people have survived -- many are here on this website. Your BIL must eat, even if it is all liquid, such as Ensure, Breeze, Smoothies, soft ice cream, etc. He needs liquids to keep from being dehydrated, as Fay said. Also, I agree the pain should be controlled, and if he is not getting the care from this doctor he wants, he needs to check with a second doctor. Don