I think what he will claim is that his orders were not "virtually impossible" to trade with. The so-called "layer" orders were in the book for a reasonable length of time. His trading program was modifying the orders to keep them a few ticks from the inside, but they could have been hit by any contra side order that was big enough to trade through all of the orders in front of his. It's not unheard of for big trades to sweep multiple price levels in the ES book.

They will have to prove that his intent was to use the spoof orders to signal other participants to trade and I'm not sure that is as much of a slam dunk as all these news articles are claiming. I.e. there is no email where he just comes right out and says "these here are the spoof orders meant to move the price etc etc etc."