Awww I love hearing someone else having compassion for their babies...Our mama's second litter was a singleton...He grew up to be a very adjusted smart Yorkie...He got ALL the attention, lol. I don't really know that there is anything you can do, except loving him like you do and making sure he is well socialized as he grows...We did put a terrycloth bear in his box and he snuggled with it from time to time. Don't worry so much that he is lonely..He will do fine.