Who says this guy is even in the usa. I can’t see how miner purchases equals tax fraud.
Some countries other than the USA call their law enforcement "feds" as well.
Maybe he's telling the truth and he just wants invoices to trick his friends.
The other possibility is he's trying to claim he bought miners in 2011 in an attempt to prove his btc is legitimately acquired. Or he's trying to get invoices with names on them so he knows who to target for hacking or extortion. Or any other number of nefarious acts.
Anyways, I doubt anybody who was mining in 2011/2012 is desperate enough to sell this guy an invoice and if they do that's their choice.
Nothing illegal, in some countries you need to prove that you are "qualified" to get permit to legally open crypto mining business. So the friends = government.
Something small as showing that you were mining as a hobby before all that license bullshit can be enough.
I don't need your name or address on that invoice, it will be modified, just the template.