Remember that it's going to get worse for him before it starts getting better -- Post-rad is kinda like having to let food sit in the microwave oven for a few minutes so it will finish cooking -- It can last weeks.

That said, the more swallowing he can do now, the better off he will likely be in the future.

Same is true for opening his mouth as wide as possible to keep everything in his jaw system flexible (search 'trismus' for more info) -- These first few weeks are apparently the critical stage -- If he can stand it with his mouth sores, brushing his teeth will help with the opening and to keep his teeth clean.

As far as taste goes, in my case I could taste salt early on, but anything sweet had an unpleasant metallic taste to it -- Safeway and WalMart carry house-brand nutritional drinks in three flavors, plus there's ScandiShake that comes in flavors and you mix it with milk.

Pete