It looks like your son will always be very devoted to his little friend. That is so sweet. Way back when Lily was spayed BF had a trip scheduled so my young niece came and spent the night trying to help me keep her restful. When it was time to go to bed she wanted to sleep in the crate with her. She got in and showed me how since she could fit in it with Peeves it would be just fine for her to sleep with Lily. I let her camp on the floor next to the crate instead.
this is our Yorkipoo and she's 3. So she's our kids first pet they experienced puppyhood with. I got very lucky, they all listen very well on how to be gentle. My son is like the puppy spoiler, always makes sure she's cozy and insanely lovey with her. I know he'll be my biggest helper when puppy comes! He's so laid back compared to my girls.lol