This article says Jake was a bit crazy — nice but seriously unstable. He was also very well-armed and Jake himself stated that he was planning to use the weapons. The job of the police is to protect and serve the public. They did that.
July4: The job of the police is to protect and serve the public. They did that.
I think July 4 has the key point. The police are not supposed to be private, on-call psychiatric help. If a person has called the police, she has turned over judgment as to appropriate actions to take. On the whole, I think this is how it has to be. The family members of a dangerous person - and the police have to assume he's dangerous, since they were called, in addition to the weapons and threats - can't be in control of the situation.
How many times do we read of deaths, sometimes multiple deaths, because a parent or spouse refused to press charges against a dangerous family member? They aren't objective.
It's a sad event, no doubt. Perhaps the author's step-in-law should have called him, instead of the police. On the other hand, that could have resulted in Jake's killing his wife and child.