if his parents are going to help him pay the rent then you have nothing to worry about when it comes to paying the rent.
So here are the 2 situations as I see it,
A: He doesn't get a new expensive car and continues to spend cash supporting a lifestyle he is used to, bar nights, dinners out, new toys etc.
B: He does buy a car and cuts back on everything above and makes the car payment every month.
I go with B since in 5 years he will have a paid for used Lexus under his belt!! Option A gives him nothing... Buying the car sounds like the better thing to do!
