That family doesn't deserve him then, someone with a heart will adopt him. They could find friends, kennel, anything but shoving him into a shelter after he went through that for them. Unbelievable. There are also plenty of farms around where if they had made the effort, they could have got him fixed and someone would look after him until they could again.
Oh I know he'll be cared for.. but I mean.. it's heartbreaking that he came back to them like that just by itself, but knowing they gave him up after he did come back like that is just a double-whammy...
poor dog.