Family member using CPAP says they feel pressure in their ear.

So bought a CPAP for a family member, they said they fell pressure in the ear same as the pressure they feel in their ear when they are in a flight at altitude. This makes it hard for them to wear the cpap while they sleep, so they are not using the CPAP (with full face mask)anymore.

They did visit ENT lots of time in the past, live in an area with pollen allergy, used to smoke but quit a month ago, were a mouth breather

what is the solution? Anyone ever faced something similar.