In a recent interview with JustJared, Ashley Benson (Hanna) said that she thinks Haleb is meant to be. "No matter what challenges they face they always get back together, so I think they’ll have a future for sure," she explained. Well, it would be pretty darned hard for them to have a future if Caleb's dead!
On top of that, we know that Tyler Blackburn was on set for Season 3, Episode 16: "Misery Loves Company," and there's supposed to be some Haleb action in the episode. (And before you mention flashbacks, remember that they always revolve around Alison [Sasha Pieterse] in some way. Since Caleb didn't show up in Rosewood until long after her death, it doesn't seem likely that the Haleb scene would be a flashback.)
The fact that Ashley Benson is so confident about Haleb's future makes us feel good about Caleb's chances.
We're sad Caleb was shot, but as long as he's alive and well at the end of it all, we'll be happy. Hanna can nurse him back to health!