When I was in the service, we frequently had to deal with young enlisted not being able to pay their bill.
Invariably it was new car payments, child support payments or both.
His car will get beat up, tell him to buy a car that is already ugly, that way he doesn’t have to get mad when his buddy pukes in the back seat or he walks out and sees a new crease in the door.
Also warn him of the town honeys, they know that the military will ensure they get every dollar of child support awarded. Frequently they will have a whole brood with a different enlisted man as the father of each.
I figure he’ll get deployed and have to make payments(and full coverage insurance payments since it’s financed) to only have it city in a mud yard with no little to no security where it will be vandalized or stolen.