I am a Christian minister and have prayed for your brother.
I highly recommend you check out the 2 books "The Hidden Story Of Cancer" and the "24 Hour Diet" featured on the following website. The author (no affiliation with me) provides what he believes after much research is the way to prevent cancer. His name is Professor Brian Peskin. I have ordered both books, and they are excellent.
He also has free videos and audios to watch/listen to. I highly recommend people wishing to prevent cancer check out for themselves this helpful information.
http://www.brianpeskin.com
Note: Neither myself, nor the author I mentioned, claims to "cure cancer," but in his books he does claim to know how to help prevent cancer. He also deals with preventing it from returning for those who have previously developed cancer and have undergone treatment to kill the cancer cells, which would likely be helpful for your brother. Well worth the investment in these books in my opinion. Both books I mentioned were co-written by him with a licensed Medical Doctor (M.D.), and he has many doctors who endorse his "Peskin Protocol" for preventing cancer.