Lesson learned: “Patching” does not work (at least not for these children). I am not fanatically opposed to corporal punishment (AT HOME – obviously absolutely unacceptable by anyone other than parents!), but it needs to be very well thought out. In most cases, the best reason not to use corporal punishment is that it is ineffective. This is because it is usually not the result of a proactive and thought out parenting plan, but a reactive way of trying to force children to act in a certain way.
I don’t see what there is to be gained by responding to this incident in a vacuum. The three year old probably has heard, “if you…then I will…” countless times from his parents, and is simply following their example. Let this one slide. The focus needs to be on cultivating the appropriate respect on the part of the parents.
This father needs to engage in a long-term plan to reestablish his parental authority, without resort to hitting his children. Don’t pretend to have all the answers; read some parenting books, develop your personal method of parenting, and be relentlessly consistent about its implementation.