What do you do when a car was sold to your son that is very unsafe to drive?

You will need to find a lawyer who specializes in Lemon Law and Autosales. Sending written notice to the dealer that they have sold an unsafe care and that you intend to use the Michigan Consumer Protection act for injunctive relief from the sale also makes sense. Give them a set period of time to make the car roadworthy and offer to deliver the car to the garage of their choice to make repairs. If the car is as bad as you say, they had to know about it.