Hi.. Thanks for writing to us.. As per your complain it looks like dry mouth and dry nose can be due to causes like: -Severe dehydration, side effects of medications if you take any, salivary gland dysfunction, nerve damage supplying salivary glands, oral infections like thrush, Sjogren s Syndrome..etc.. The first thing that is needed to be done is to rule out the exact cause of dryness.. It is probably appearing to be reduced secretions.. As of now he can take steam inhalations with a few drops of Eucalyptus oil to refresh breath.. He can use a humidifier in his room as moist air can help in moistening the nose and mouth.. He can also apply Xylitol patches in his mouth for lubrication.. Hope this helps.. Regards.