OP, is there an existing car owned by either families that your step-son could use initially? He could save some $ while working to put towards the car.

This would ensure he would not commit to car payments until he has a feel for how much he is working/earning.

Door dash will say yes to anyone. Tne door dash drivers after all the effort might not be getting even minimum.

And if you think there is no contact, guess again. Different restaurants do different things.