16 year old new in advance of stolen property...

Let me rephrase....In Michigan, can my 16 year old be held accountable in any way if he new in advance of someone who was going to steal 3 golf carts, but he told no one?

His friends asked him to participate in the theft 1 golf cart...he declined and told no one.
His friends sold golf cart #1. The police do not know of this incident.

His friends asked him to participate in the theft 3 additional golf carts...again he declined and told no one. His friends stole the carts and got caught by the police.

I am of the opinion that the police will eventually find out about cart #1.
His friends stole it. His friends sold it. He knew about it before they stole the last 3.

Can my 16 year old be held accountable in any way if he new in advance of someone who was going to steal 3 golf carts, but he told no one?

You have not given much information, but there laws re aiding and abetting and also for being an ascessory to a crime, so it would be best that you tell a trusted person who can advise you and help you get legal assistance if needed. If it has not happened yet there may be a way to report it without identifying yourself and if it has, then cooperating may be your best bet, but you may want to get legal advise for your exact situation before taking any action or to be prepared if you are contacted for questioning by the police.