From the website:
“Only registrations of men born on or after January 1, 1960, can be verified through this system.”””
If he wasn’t born in the USA- then he isn’t in the system...
Not true.
If he wasn’t born here, yet lived here legally or not he’d still have to register.
“NON-CITIZENS
Some non-citizens are required to register. Others are not. Noncitizens who are not required to register with Selective Service include men who are in the U.S. on student or visitor visas, and men who are part of a diplomatic or trade mission and their families. Almost all other male noncitizens are required to register, including illegal aliens, legal permanent residents, and refugees. The general rule is that if a male noncitizen takes up residency in the U.S. before his 26th birthday, he must register with Selective Service.
DUAL NATIONALS
Dual nationals of the U.S. and another country are required to register, regardless of where they live, because they are U.S. nationals.”
So unless he was here on a student or visitor visa was part of a diplomatic or trade mission, or was a special agricultural worker with a I-688AA visa he would have to register.