Why doesn't mom have to worry when her 3 year old boy threatens to hold his breath until he dies?

He is just a 3 yr old all you have to do is pick him up and hold his hands away from his nose so he cant block the airway don't freak out. When I was 5 and my parents divorced i pulled a knife on myself and my mom she freaked and called the cops when all she needed was a pillow or something the block the knife while grabbing my hand then getting the knife from me. Don't worry about kids under the age of 8 threatening to kill themselves or another person