I think that we need to remember that this family is reacting to the death of the boy's sister, the mother's daughter.
Our culture does not teach healthy responses to death; on the contrary, we hide it away.
I don't think that we can comment on the rightness or wrongness of spanking (a nice word for what is usually hitting out of anger and loss of control by someone much larger) in this situation, but perhaps comment on how tragic it is that these people are put into the television spotlight and the boy is turned into a monster, the mother turned into Frankenstein, because of a sound byte put out on the internet, and presumably due to not having help to deal with profound grief and loss.