If that guy is running 20 alphas he’s in breach of the eula/tos and begging for a ban if CCP find out.
It doesn’t matter how you do it the rule is still one alpha.
Mining drones also require targeting per rock just like lasers. There is no aggressive type mode for them. Well unless it’s been added in the last month or two, haven’t used mining drones super recently. So I don’t see how it mines more than the max alpha Battleship miner. Not even sure the Vexor mines more than a venture considering drone travel time drops you below theoretical max yield.