Welcome to the forum.
Poly-orchidism is the incidence of more than two testicles. It is a very loose congenital disorder, with fewer than 200 cases reported in medical literature.
It is a must that he needs to be examined.
His age fits
with testicular tumour, but does not mean he has one.
It can be a just cyst
of the epididymis
Nothing can be said without examination.
Advice him not to lose the chance of cure if detected early and he will come, i am sure.