Hi and welcome to HCM.
It sounds like typical biliary colic
caused by gallbladder
stones. It isnt very often in his age but definitely can be found. Other reason for it are acute hepatitis(alcoholic,toxic or viral). This isnt emergency if his symtpoms doesnt progress but it should be evaluated and ultrasounds and basic blood tets should be done.
If he experience repeated pain, vomiting
he must go to ER.