Hi Terri, this definitely sounds like sleep apnoea to me.
Did he have any of these signs prior to his treatment?
Do you think that there is still some neck / throat swelling from his treatment. Sleep apnoea usually affects the overweight and those with thick necks. If it helps your worry remember that he will keep breathing. Once the carbon dioxide levels in his blood get to a certain level he will breathe.
Wishing you a good nights sleep,
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!