Given what you have posted as his stage he is a pretty early find, and the doctor's treatment may indeed be adequate. That does not mean there will not be some side effects, but certainly likely less than most of us have had to deal with. What I am always afraid of are the things that do not show up on the scans, the micro mets.

You mention chemo, and perhaps with no involvement away from the original lesion there seems to be little call for the use of it except prophylactically. Some institutions are very conservative in their treatments, others, particularly the big guns, tend to lean in the other direction. You don't mention where he is being treated and if this protocol is one derived at by a multidisciplinary team.