yeah, I ahd chemo too and scheduling was tricky for me. Is he having amifostine (ethyol) shots beforehand? If so, he will need to get extra hydration before the shots and then the rad needs to follow the shot almost immediately, ideally within 15 min-half an hour. The extra hydration takes some time , so you don't want a really early time.

But if you are having chemo too, you will most likely have that after the radiaton, and usually it takes several hours so you can't go too late either. As I recall, my rad time was 11:30 AM and that made a really tight schedule for the chemo after. Ideally, 10:30 probably would have been better but I didn't have total choice of times because it was a very busy facility--as they all are.