All cats react differently to anesthesia. Keep in mind that both your male and female cats underwent major surgery. Most likely the anesthesia has not completely worn off for your male cat.

I have a male that was cryptorchid and he was back to normal in a day or so. Both my kitties were very tired when they got back home...they both slept for the better part of 2 days.

If your cat does not become himself in another day then definately call your vet back and voice your concern to the vet.

Hope both your babies are feeling better soon.