Clementine Ford has expressed exactly my thoughts on the matter of murder suicides.
She is absolutely correct to suggest we have to stop valorising controlling, egotistical men, who commit acts of violence, as "good blokes" who have simply "snapped".
One of the reasons given for Peter Miles actions was that the serious illness of another of his children pushed him to the brink.
By killing his wife, daughter and grand children Miles has failed utterly to support and nurture his unwell son. Instead, he chose to turn his attention onto to his own suffering.
He has left his surviving son to deal with a serious health condition in the face of unimaginable grief and the terrible knowledge of his father's betrayal. I wouldn't be surprised if Miles' son suffers survivor's guilt as well.
Murdering your family is not the behaviour of a "good bloke".