Does Flynn Need a Sibling?

In  honor of National Sibling Day I started thinking about possibly getting a new dog/puppy. I have thought about the idea often but I am not sure if having another dog would be good for Flynn. He loves my mothers dog and most other dogs he meets. He has never reacted aggressively to anything or anyone. I think it would be good for him to have a companion. I have thought about adoption, but I have really started to think about fostering dogs. If anyone has experience on fostering I would love your advice and tips. Thanks to all!!

Love 

Brooke