Sorry, I have to strongly disagree - at his age, and given his general pessimistic nature, he shouldn't hold large amounts of cash waiting for opportunities. He's young and has 30-plus years of investing ahead of him. He should be 100% invested - markets end up ahead over any sort of timeline like that, usually by a very large amount. At his age, waiting around for great opportunities is just a form of market timing, a notoriously bad idea. For him, it's much better to just get in the market 100% and continue to DCA. This is even more true given his pessimistic nature, which is a huge handicap in the long-term investing game.
But I've seen enough of his posts to realize that he thinks he knows better, that everyone who tells him this exact same message are dumber than him, and he won't listen.