Neither, in my experience. Maintenance.
My doctor told me NOT to try to restrict calories for at least 6 weeks post op. Just sit tight, eat healthfully and let yourself heal. I still lost a little weight in the first couple of weeks just because I didn't feel great, was in pain. Your friend's surgery may be less involved.
When he's healing, he won't be able to lift heavy for a few weeks. He won't want to be on a calorie surplus if he can't train hard.