Dr. Hibberd’s answer:
 

Sleep apnea is associated with following symptoms: excessive daytime sleepiness (hypersomnia), loud snoring, (usually more prominent in obstructive sleep apnea), observed episodes of breathing cessation during sleep, abrupt awakenings accompanied by shortness of breath, awakening with a dry mouth or sore throat, morning headache, and difficulty staying asleep (insomnia).

If he has any of the above symptoms in addition to his snoring, you must visit your doctor who can test him for sleep apnea. Testing is done by a sleep study. But be sure to talk to your doctor about the loud snoring, especially snoring that's punctuated by periods of silence.