I think that's only his US day trading strategy, all other trend system in cash?
The above is the only relevant thing in your post.
I'll write a book on: "when to stop trading and go on holiday". $50000 for you, it'll save you $310k in loses.
Let's not pretend that didn't look like doubling down. It's not his track record or saying "he sucks" that I'm interested in. I know he's skilled and been around a long time.
It's how and why these trades came about. And the reasoning behind continuing for so long.