make sure it's clean (no other cat odors in it)
you might want to keep him confined to just one room, preferable a room where you can clean surfaces off
this assuming he IS a tomcat, assuming also he's been neutered
then yes, stick him in the litter box .. and make sure he has food and water on the other side of the room
keep things as quiet as you can ... and give him a towel or something like that to curl up on
he will make sure most everything has his own scent on it, to begin with ... if you are lucky he will never have "sprayed"
good luck ...
Candy
(you probably know all this already, it just bears repeating)