Pierre has always been a chronic snorer, much to the dismay of his wife hazel. for the last three months, he has been waking up in the middle of the night gasping for air. he most likely suffers from

He most likely suffers from sleep apnea.
Sleep apnea refers to a breathing disorder; sometimes people experience difficulties breathing or they completely stop breathing during sleep which lasts for a couple of seconds but still creates discomfort for the person suffering from it. It can occur a couple of times during sleep and is followed by snoring, which is a common thing for Pierre in this example.