Opening of House of Wax (2005)?

"In 1974, a woman is making a wax sculpture in the kitchen while her
son eats breakfast in his highchair. Her husband enters with another
son who is shouting and kicking. The boy is forced into a highchair
and strapped in place by his father. After being strapped and taped to
his chair by his mother, he scratches her hand. She then slaps her
child across the face."

I don't get the opening of House of Wax (starring Chad Michael
Murray), I take it the little boy in the high chair was Bo and the
other boy who was dragged in by dad was Vincent, but why was Bo
treated better than Vincent?

Thanks xx