Meaning: It would be wise for him to cease eating in the vehicle.
Choice of Words: Should is used to express advice or a suggestion. Stop means to cease doing something.
Alternative Expressions
It's not allowed to eat in the car.
Meaning: This means that eating food inside the car is not allowed.
Choice of Words: The word "allowed" means permitted or acceptable, "to eat" is the act of consuming food, and "in the car" refers to the inside of a vehicle. Together, this sentence means that consuming food inside the car is not permitted.
Please refrain from eating in the car.
Meaning: This means that the person is being asked to not eat food inside the car.
Choice of Words: The word "refrain" means to hold back or abstain from doing something, "eating" is the act of consuming food, and "in the car" refers to the inside of a vehicle. Together, this sentence means that the person is being asked to not consume food inside the car.