His feet are looking pretty good, but I think it will be another week or two until you will be able to know for sure if he's going to lose toes. The "index" toe on his right foot looks a little darker than the others... Nothing you or your chicken sitters can do but wait and see.
All in all it's probably safer to keep him inside while you are gone, but if it's just him alone all day for weeks he might get lonely and depressed. If he were mine I'd be letting him out with the flock during nice weather (provided reintegration went well and no one was bullying him) and keep him inside at night/during freezing weather, but not sure if that is an option with your chicken sitters.