Loved the book and the movie Free Solo. In my opinion, Alex is not alone on the wall, but his father's spirit is with him. I don't know if he has ever been asked about that. It seems Alex's dad introduced him to climbing, and was a huge supporter in his youth. So what's the worst that could happen to Alex if he ever fell from a free solo? He would be reunited with his father. Alex is actually honoring his father with every climb he does! GO ALEX!!!!