They take Bill home with them, where he plays an important role in the Scouring Of The Shire (giving a certain someone a swift kick in the rump). He becomes a great leader of ponies and lives happily ever after to the end of his days.
Oh what a relief that is... and now that you mention it, I remember the part about the swift kick! - Thanks!
I love a guy that gives me spoilers when I can't look things up!