Get A Job, Son.
He has worked real hard learning to tile, doing tiling jobs, and mowing and furniture moving.
Have a serious talk to your son about how expensive it will be if repairs are needed for this type of vehicle. You may have already done this
Have it checked out by a mechanic, unless you’re acquainted with these types of trucks, it could save you, or at least prepare you, for a financial hit.
Who is paying for the insurance coverage?
If he’s earned the money himself, if he’s going to pay for things out of his own pocket, I’d reluctantly give the go ahead.
FWIW, I’d gone through this with 3 sons. They always think bigger than you’re prepared for!
he needs to get a FORD.