So sorry but you should have no regrets. You were kind to him while he was with you outside. One thing I've learned you do your best but it is almost impossible to save all the cats that need saving. You do your best and thats all you can do.
I love that word - choose - in regards to ferals. Feral cats do not start out trusting humans but they can and do, overtime, choose to trust their own caretaker either from a relatively close distance or closer - to begin rubbing on legs or allowing pets. It is amazing to hear about feral cats choosing, even in their senior years, to give up the outdoor life and begin to ask their caretaker to take them in - they choose self-preservation in their old age. I have heard so many stories of this from my feral mentor who runs a large TNR group in Illinois. It is absolutely miraculous how many feral cats begin to want to make that life change.Thanks Krz - I do know what you mean they choose us