The fact of the matter is that some people just don't value an animal's life as having any worth. It can be due to religious beliefs, poor experiences with animals, broken/nonexistent relationships with them, or really any number of things. There's basically no way you could ever get him to really appreciate the life of a dog, he'll always see it as something worth much less than another person would. I wouldn't have believed him if he did apologize for the deaths of those dogs.