Having nothing to do after retiring is one of the worst experiences in one's life. Such people get upset when they no longer get the attention, applaud and command they enjoyed over the decades and such things have serious consequences, I tell you. Anything leading from just depression to Alzheimer's can actually be very damaging to the individual in particular and the family as a whole so m actually happy to see how concerned you are about your father. But for us to suggest, like Zia said, you need to tell us about his hobbies and interests first.