It is a kind of etiquette to bring some gifts when visiting a friend's house. It is most appropriate to give gifts according to the host's preferences. If your friend likes to keep pets, it is also good to give some pet-related things. I have a few small suggestions:
1. He already has a dog at home, so you can bring some things related to the dog, such as puppy clothes to decorate the puppy, a puppy rope, and things and food for feeding the puppy. It is best to buy him a book or magazine on how to keep a pet. I believe he will like it.
2. If your friend has more time, you can give him another pet, a different dog or a bird, a kitten, etc., so that you can know what else he likes to keep in advance.
3. In addition to giving these things he likes, you can also bring some regular gifts as a thank-you gift to the family, such as giving a bouquet of flowers to his wife, and choosing a gift for his children.