A friend of mine had two chihuahas. One died about a month ago from liver disease, and the other got run over two nights ago. They have a little boy who is 4 years old. They want a big dog for him, but they don't have very much experience with training dogs. What breed would you recommend for them? They need a dog that is smart, not too hard to train, and would love kids. I would appreciate any help you could give me.