I think he'd be fine with it. Babies are so facinated by other kids. I would think the younger the child you adopt the better. Where are you adopting from? The reason I ask is because babies learn how to bond with people when they are very very young. I don't know much about adoption, but I do know if a baby isn't held and loved very early on they sometimes have a hard time accepting it later on. It's a form of RAD (reactive attachment disorder). I would also want to know what the child has been through in their life. Abuse or neglect can cause a child to be very uncontrollable.
I worked with a young man who was adopted when he was 7 months. He was the sweetest and most incredible kid, but he couldn't stand affection. After reading his history we learned that he was never held. It was very very sad.
Good luck with whatever you decide. I think it's great that you are considering it.