@Robin_n_Jack:
Last night, Jack had fallen asleep on the couch, after I had gone to bed. DH woke him to put him in his crate for the night, and Jack started snarling at him. Apparently, he snarled at DH, then ran over to the closed bedroom door, where I was sleeping like the dead. He came back, let DH take his collar off, then snarled and ran back over to the door. I guess he ran back again and DH kind of pushed him in the crate.
Did he snarl or did he make a growly type sound? If he growled/snarled when he was woken up to be moved, I would suggest trying to wake him up using voice to call him off the sofa or where ever to get a treat and then put him in his crate.
Sometimes mine make what at first sounds almost like a growl but is actually a playful noise, it has a slightly different tone and rythym and they dart back and forth trying to start a game of "catch me".
@Robin_n_Jack:
He has never done this before. DH is gone a lot- like 6-8 weeks, and he is usually only home for about 2 weeks in between, so I was always concerned about DH being able to show he was alpha to Jack. Jack definitely knows that I am in charge, but this is really the first time he has shown any aggression towards one of us.
Since your husband is gone for such long periods of time, it might be helpful when he comes back from a long trip to have him hand feed Jack. Hand feeding is great for helping to build a bond between human and canine.