If your friend votes
Covered that already:
he'd have to vote for once to catch me.
There's a reason I'm referring to my non-voting friend as non-voting, it's to imply that he doesn't vote, so that kinda sorta precludes the whole "he votes" thing anyway because the premise is that he does not, in fact, vote.
they also probably didn't bother to register.
He was born with a penis, he's registered for the draft since 18 and therefore to vote since 18 as well, because those are coupled for people born with a penis. Unless he changes his name (unlikely) or political affiliation (for what, to vote in primaries? He doesn't vote.) Technically he should re-register because he changed his address, but again why would he if he doesn't vote? Literally no consequences could befall him, there's no incentive for him to do it. Bro I'm still registered at my mom's despite having bought a house (which the government knows about because it's public info), because it's easier to just drive 15min to my old polling place every few years than to go fill out a form, been doing it for years, and I vote! There's no way in hell he's ever going to change that address from his parents' just to continue not voting.
You need someone you know registered
Literally all 18+ AMABs in the US
and you know isn't going to vote.
Know any AMABs that don't vote? There's one right there. Not as uncommon as you might think.