This sounds like an account by someone who has never climbed a cliff or held as sleeping child.

You need to hold on to a cliff face to go up. You can't hold a kid's ankles while holding on to a cliff face. Plus you need to change the positioning of your shoulders and neck a lot on a climb. No way a slumping kid will balance.

At MOST, Andy and his friend walked up a hill while giving a sleepy but awake tot a piggyback. But I still think it's entirely fiction.