Like this...
Government Explained 2: The Special Piece of Paper
Law without Government
TANSTAAFL:Anarchy isn't easy? No, but it's dangerous. Someone has to be in charge of the anarchists and they don't like that much. In the end, anarchy turns on itself and the strongest, most brutal anarchist becomes the dictator or king.
Where's the argument here? Can he support his contention that "someone has to be in charge of the anarchists"?
The keyboard is mightier than the gun.
Non parit potestas ipsius auctoritatem.
Voluntaryism Forum
I would tell them to make an argument, or else there can be no response given
"As in a kaleidoscope, the constellation of forces operating in the system as a whole is ever changing." - Ludwig Lachmann
"When A Man Dies A World Goes Out of Existence" - GLS Shackle
I think he is trying to make the point of the communist vangaurd, which can be taken as the capitalist robber baron fear, or, universally, the iron law of oligarchy. But, he doesn't actually make the point in relation to anarchy "needing" some kind of regulation for the ubermensch that will rise in their particular trades like I think he is hinting at. If he does make the point, tell him that it is universal to social organization not just anarchy.
Just tell him you're not really an anarchist and you want to replace government police with private police.