Leaving Security Area On A Lay Over

My son is a Canadian citizen who will be vacationing in Las Vegas via Westjet.  His return flight is from Las Vegas to Kelowna, BC, to Calgary.   When in Kelowna he will have a two hour lay over before resuming his flight home to Calgary.  We live in Kelowna and would like to visit with him during the layover.  Will he be able to leave the security area for the layover time and then re-enter when his flight his called? Thank you.