Not necessarily.
But it's a major operation (despite the short hospital stay) with everything being shoved around, bits removed & gas put into the body to move organs out of the way.
It takes a while for the gas to dissipate & gravity to allow the organs to slide their way back to the usual places once he's up & walking.

Plus there's always concerns about straining & damaging the surgical incisions.
He'll probably be given some kind of constipation medication regardless.