They can still press charges for at least a year, sometimes up to 2 years depending on the charge.
For Civil lawsuits, they can sue him for damage to property, they can sue him for up to 6 years.
But, the good news is that most likely, the police will not charge him at this point. They would have to sue him (actually they would sue you as his parents), which they probably will not do.
Attorney
Experience as general attorney, in house counsel, SSDI, Family Law attorney, and law professor