BUT now they have willfully damaged a pretty expensive pickup truck belonging to another neighbor. 

Give the son 10 days to collect the belongings, and then trash what's left.

Although a month may not be long enough to see a person's true character.  

You must make an appointment with a sheriff's deputy to supervise keeping the peace while your people move the belongings out on the curb.

Wait until the property legally belongs to you before treating it as yours.

@David Smit"Where imposture, ignorance, and brutal cupidity, are the stock in trade of a small body of men, and one is described by these characteristics, all his fellows will recognise something belonging to themselves, and each will have a misgiving that the portrait is his own."

We’re actually the 4th house that has closed, but only the 2nd to have moved-in some of our belongings (we’re waiting to move in valuables until we have a security system in place, which requires a landline or internet...). 

However, if you belong to their associations or know them personally all of a sudden you get a split or referral fee. 

Drink a liter of water with a scoop of wheatgrass in the morning3.

They have already taken 1/2 of their belongings to Nebraska where they plan to move.