Poor Bentley! If you think Sadie's going into heat is hard on YOU - look at HIM! And he doesn't even understand what's going on. His hormones are in a dither because of the scents Sadie is giving off, and he's lost his companion and playmate at the same time.
He's going to need a Doggie Psychiatrist when this is all done
. It's a shame you couldn't get him in earlier; by the time he gets there, the worst will be over with. But good luck with them both.