Shauna
My mother in law was recently diagnosed with colon cancer and she had lost a lot of weight. She is still losing but not as rapidlly since surgery. They took sum of her colon. The Tumor was connected here. I'm not saying this is what your brother has, but they told us the cancer feeds on a persons food that they consume and most nutrients don't get where they need to go. And also that cancer feeds on sugar. She drank ensure to try and get nutrients and calories. The stress of dealing with cancer alone, has got to have some to do with weight loss, too. Good luck to you and I will keep your brother in my prayers. God Bless You this Christmas season!