Don't ever give up hope! When I was a kid, we had a cat that I let in the house at the start of the Blizzard of '78. She was with us for 13 years, but every so often, she'd leave for weeks at a time. The longest was for almost a year, then she'd show up like nothing had happened. Same thign just happened to a friend of mine in Mass. They took his father's cat in when he passed, and the cat disappeared a few weeks later. He just saw him in the yard suddenly, after about 5 months!