If you can't find him a 100% indoor home, I'd consider putting him down. He won't be able to hunt, he won't be able to see predators (cars, coyotes, dogs, etc) coming, and he will have to rely totally on sounds and smells to navigate. The plus side is, he hasn't had his sight, so he won't miss it. Animals tend to be very good at coping with disabilities, especially since their hearing and sense of smell is far more keen than ours.

However, his chances of survival are very much diminished if he lives outside. If you're OK with that and he seems to be able to cope, then by all means, let him live outside.