Hi gmomluvsvv,
My peeps dogs always stick very close to the peep who just lost a mate. I'm sure it's something in the programming; Though it's really sweet though isn't it?
I've also had the pets take a liking to one kid and follow it almost exclusively throughout the child's life. I have a family now that has a set of triplets, a single son, and a set of twins. The dog took up to one of the triplets. I have screenshots of him sitting by him at different times throughout his life. I think that's just so sweet!