They keep him. In chapter 1, page 44, Mashahi said they were purchasing him. Then on the next page, we find they'll provide the medical care his brother needs.
http://www.mangago.me/read-manga/pet_keiyaku/tr/125892/page/44/
Yeah but their should still be a little more
I think we'd all love more
Very true but their is a lot of big fans of yaoi work but a lot of them should have a little more to the story line but that me talking
I remember reading this as only one manga but the writer and the artist added a bit more I'm thinking that their should have more to the story like how does he get sold to or does they keep their pet?