Yes, it is normal that he has trouble eating at 3 weeks post Tx. This is the point where the effects of the radiation are peaking and it should very gradually improve from here. Measure progress in 3 week increments. The secretions should just start to be improving about now also. The secretions can sometimes be managed by decongestants but they make the dry mouth worse. A humidifier will help a lot - I still use mine 15 months post Tx.

Many believe, going into this, that radiation is the easier course but it is more difficult than surgery. It will take at least a month of recovery for every week of radiation. It is a very slow process, you must be patient.

Make sure that he maintains his fluid uptake (2-3 liters of water a day). Stay on top of pain management, infection, thrush and constipation issues. Liquids are probably all he can tolerate orally - try milkshakes and things like that. Stay away from anything acidic such as fruit juices (at least orally anyway).