What to do about dry mouth

My partner has had his PEG tube for a few months now and we’re careful to make sure he’s hitting his water goal everyday, but he’s really struggling with dry mouth.

He can’t eat or drink orally right now (we’re currently working with a speech language therapist to help him re-learn to swallow without aspirating) and he can’t use most products like biotiene because he’s currently dealing with mouth blisters from pemphigus and biotiene along with anything too acidic or minty will burn his mouth and irritate the soars.

Does anyone have any suggestions?