Wasn't that just the food that lady made for him?I don't think that he's a good person. Cause i remember there was a scene of him disposing a bloody bag
Or he went full hunter instinct and didn't see the car.So, one of two potentialities: Either he's still super crazy and just didn't want the cat to die unless he killed it, or the ghost cats are just attracted to him because of how nice he is to cats and the big one is following him to eat the cat ghosts.