Sometimes when older people are alone, day in, day out, they get like that. I know a couple of people like that. I cut them some slack because I can imagine how awful it must be to be alone all the time. I would cut him some slack, listening for say 20 minutes will help him.
If he is alone, he also may well have almost lost the art of back and forth conversation.
Elderly fellow gran has become loudly racist
Army horses loose on London streets
Narrow miss. Bus and student on his mobile