Hmmmm....I only know my own dh's experience, which is a bit different than your dh's, but here it is, FWIW. My dh was in pain on and off for about 10 years (yes, you read that right), and then his disc actually ruptured. So he had emergency surgery, but not until a few days later (long story). His recovery time was about 3 months. I'm not saying this to discourage you, only to tell our story. Since your dh is having his done before the drastic event of having it get so severe that it ruptures, it makes sense to me that his recovery time would be less. A co-worker of dh's who had a similar surgery (without the rupture) was only out of work for about two weeks.
I could say more, but I'll stop there. Hang in there!