I think it combines with making us feel sympathy for the zombies. Showing us the zombie Major killed as a family man and father, showing us the loss the man's children felt.

Especially when you keep in mind that like Lowell he probably was a client/victim of Blaine's, and at best, he did every effort not to look into where the brains he ate came from.
(just imagine, the man had children the age of those streetkids that Blaine served to his customers, so how likely is it, that he didn't have at least a few flashbacks to give him a hint of the age of his meals.)