I know it is hard. It is a situation where you need to prepare for the worst, yet can't stop looking every time you leave the house! We had an indoor cat who got out and was gone for 17 days (in February, in Minnesota!) Went
through the shelter visits, let all the neighbors know, etc.
Then, one day, our next door neighbor called, and said she had our cat! He had been hanging around the empty house across the street. He was very thin, but he was OK, and obviously had been finding things to eat. Turns out he was a mouser, and we didn't even know it! Came in handy when we had mice move in the next winter!
I guess, I just wanted you to know I have been thinking about you guys, and hoping you will see him again. It is hard to be constantly searching, though, and at some point, you need to let it go. Cats are amazing survivors...you may be surprised yet.
Best wishes to you and your family!
Lou