Hello and thanks for your post,

Sometimes treatment can be paused to give the patient a break from taxing treatment. But as nurses,  we are not in a position to give a firm medical opinion on this. His cancer specialist will have to discuss this with him, and the pros and cons of suspending any treatment plan. There may be an option to reduce the dose as well, but I don't know for sure. There are medications that can be prescribed to help a sore mouth, so he needs to speak with his doctors. 

Best wishes,

Vanda