The driver seems to have no trouble with wasting. The engine should've been turned off while the car woudn't have moved for more than a minute. (of course not when the weather is extremely cold or hot so that the airconditioning is absolute necessary). If not out of care for own pocket than out of care for the environment. The less consume, the better, and if we have a chance to choice not polute the air for a minute or two we should take that chance.
Why don't you TELL him to turn it off? Do you even communicate?