I'm afraid we had this situation recently with Carlos - left to fend for himself. We had to give him back too.
One thing is for sure, though, if Carlos is seen booted out again, and he's in that same state of neglect, whoever picks him up won't be searching too hard for his owners.
All you can do is be Lucky's guardian angel and watch for him on the streets. I wonder if he's been chipped yet...? Pretty hard to claim ownership without them these days.