Not doing the exercises, for the facial muscles and those used in masticataion, will make it difficult to open his mouth fully when this is all over, for his neck it will leave him with a limited range of motion. He needs to get off his butt and do this stuff, because once trismus sets into the muslce groups it is very hard, if not impossible in some patients, to reverse. At the very minimum he should be concentrating on maintaining the ability to open is mouth using a Therabite or wooden tongue blades every day from the begining of treatment to months after it is over. It's tough to survive this cancer and then find out that you can't open you mouth enough to enjoy eating again when it's all over!!