He may well be depressed. It also may be that he is only willing to be around family because he feels less and less able to interact with people and situations where he doesn't exactly know what to do. Has he shown any signs of memory loss? Sometimes, and please forgive me for mentioning this, Alzheimer's brings symptoms of irritability, unreasonable attitudes, fear, and anger. Perhaps you should talk to someone professional by yourself, and get some advice before you do anything else. You say he has never liked to talk about substantial things, and has never really enjoyed the traveling part of holidays. Maybe he has a sort of anxiety that he has been fighting all his life. Very good luck to you in sorting this.