This is not the least bit sketch
I don't understand how trying to get authentic, but genuinely and obviously fake money is sketchy? If this guy wanted to take a fake twenty to a gas station and buy some shit I am willing to bet he wouldn't look for a fake bill that is red and white.
He wants it to look like he has more money then he really does. He most likely wants to mix the fake money with real money. If he wants enough to fill a briefcase then I would speculate that he wants to buy bitcoin, plans on buying enough so that he would need to fill a briefcase with cash, would show the seller the briefcase full of the mostly fake cash, have the seller send him the bitcoin, give the seller the fake money and then leave
OP owns a Bitcoin ATM in Canada and is more then able to be figured out identity-wise through google and as such. Doubt he's planning on scamming here.