Hi and welcome to HCM.
Prostate cancers are much common in his age than testicular,but cancers arent the first thing to think about. This is probably prostatitis
with enlarged prostate
which is very often and it is associated with pain in testicles. No matter, it should be frequently followed up by ultrasounds and PSA check ups and if any abnormalitiy is show prostatectomy
can be performed which is almost a routine procedure today.
There is no need to be concerned. If he notice testicular swelling or redness
it mught mean something but pain isnt worrying symptom.Wish you good health.