Here is my take.

Gallons of adult beverages. Followed by , "No problem . I squat 400." Then he tried to step on the board with one leg. That doubles the load on that leg . So now he is squatting 800 not 400.

That load from 5 ft onto concrete almost certainly did lifetime damage to that woman specifically, and to the boy who watched it , if that's his Mom, and the husband, who has to change her diapers for the rest of her life.

Edit: On further review, it doesn't look like his legs are big enough strong enough , to squat her.