Hello and welcome to MedHelp's forums. So, this is something he may not be aware of as it occurs during sleep, correct? But you are observing it so please do make an appointment to discuss this with his physician. Here is some information on breathing disorders during sleep https://
www.medhelp.org/lib/breadiso.htm Your husband likely will require a sleep assessment to understand the breathing changes that are going on.
Please let us know what his doctor says. Best of health to both of you.