My husband had a Parotid Gland Saliva Lymph Nodes and a little bit of the muscle removed due to Cancer in the Parotid Gland. He had 6 weeks going daily Monday to Friday to have radiotherapy which he finished just before christmas last year. Lately he is sleeping a lot coming home from work and sitting in the chair and within 5 minutes he is asleep and will sleep for an hour or more which on some occasions i've had to wake him up. Is this normal or should we be concerned and go back and see the Dr ?. Any advice will be greatly appreciated.