Carol,
My mucus lasted until exactly 3 weeks post and my mucositis until 5 weeks post so he is in a similar range to where i was. But then suddenly it all starts to improve. I truly thought the mucus might kill me; was by far the worst sx for me. So just help him through and keep reminding him that there is a light at the end of the tunnel. It really DOES eventually go away. Also, I resisted narcotics at first but actually ramped them up during the mucus phase b/c the only thing I found to decrease it was percocet. Weird but it gave me some relief. Going on walks also helped me as I would be distracted at least temporarily. Good luck and I hope he feels better soon!