Hello Susie, I could not seem to gain any weight until about two years out. I would eat any and everything I could. I did not continue to loose any weight once the treatments stopped. Hopfully he will turn the corner soon. Have him record exactly what he eats each day for a week and verify that he is getting enough calories in. 2500 calories eaten should stop any further loss of weight. Anything less than 2500 calories might not be enough because his body is busy repairing itself (and using more than the usual amount of calories) Also be sure he is getting added fat and protein as well as vitamin rich foods.