Treatment decision making-- chemoradiation or no treatment

My husband was diagnosed with oropharynx cancer - Stage 4, T3 N2c M0 - and had successful surgery at the end of June. He's now trying to decide about doing chemoradiation or no treatment. The doctors recommended the chemoradiation because his lymph nodes were involved with extranodal extension and although most of the margins were good, there was one very small margin. He's 81 and already has memory problems for which he takes aricept. Pain pills make him delirious, so he can't tolerate those. I don't know if the pain is worth the gain. The radiologist said he will never be able to swallow again.He although thinks without treatment the cancer will be back within a year. Everything I read suggests this cancer comes back no matter what treatment you have. He's getting along fine right now - although he does have a g tube. His children and I will go along with whatever he decides. It's just hard to see him suffer and maybe lose his mind and his quality of life, just to have it come back. This decision is just so very hard. I change my mind every hour. Any words of wisdom you could offer would be welcome. The people on this site have also helped my brother who has renal cancer. Thank you so much!!