Welcome to YT
You might want to try bringing his crate up to your bedroom and put it on your night stand or beside your bed. He is probably just lonely downstairs at night and missing you guys.
The fact that he's in the same room as you might stop the barking all together or if he starts barking all you have to do is put your hand over the side of the bed and pet him to let him know your there.
My Bella's crate is in my bedroom and she never barks.
Good luck !