how does a citizen get an ID when...?

Hi everyone. My boyfriend is a US citizen. He was born in Canada but has been living in the US since 1985 (for more than 23 years now). A few months ago he lost his wallet containing his driver's license and his social security card. When he went to get a new ID, he was told that he does not "appear in the system" and that, since the only legal document he has left is his Canadian birth certificate, this is not enough to be established as proof of identity. His parents tried to get the high school he went to but no records of him studying there could have been found because some years ago that school was destroyed to its grounds after a fire. We don't know what to do and my boyfriend feels like an immigrant with no legal status. We are desperate and we need help.

Proof he has legal status doesn't disappear. Does he know his drivers license number? SS number? What about his job? His employer? Who told him he doesn't appear in the system and to what system are they referring?