I'd be just heartbroken if either of my pups were lost!
I'm glad you were able to give the little guy shelter & love while he's been with you.
I also want to mention that it does not take long for a coat to become a tangled mess. PLEASE do try to find his owner; they're tips in the YT library (if someone doesn't post them I'll do it when I get home.)
As for the shying away when you go to pick him up, my Tuffy does that & he's never been abused.