Is it normal for old people to prefer the company of their pets?

My grandfather is almost 80 and even when we visit, he would rather sit with his old dog and pat him quietly in another room than talk with any of the family members. He will say hi when we get there but will so wind up in the other room away from all the people and sit with his old dog. I think he feels the dog cares for him more than any of the humans. Is this normal for very old people?