Infield08-
Senioritis is a treatable disease!
I believe Dad is on the right track. Don't know what your arrangements are about the car. We had our son sign a contract about the use of a car. He had to maintain a 3.5 in order to have use of the car. Our insurance company also gave a nice discount for this GPA. We simply told him that if he could not maintain the GPA, the insurance would be too high for us to afford and he would have to make up the difference.(Pretty hard to do for a full time athlete of two sports in HS). If he could not provide the extra $$ the car would sit until he could come up with it. No senior wants to depend on others for rides. I must say that it is hard to recover from a C unless he gets his act together. Even though he would still pass with a C, I am sure you are letting him know that your expectations are much higher as they have been all along.
He must know that once he hits the college enviornment, it will be all him. Once you get in trouble with grades in college (baseball) you are on probation and have to attend many hours of study hall the next semester (all of it) until you get grades - not grade checks. At my son's school if you maintain 3.5 or above you have minimal study hall since you have proved you can manage on your own, all others live in study hall - a place you do not want to be for a whole semester. The last half of senior year is not the end, it is only the beginning.
All you can do is inform him of this information. If he chooses to ignore your advice, he can be a non-driving senior with a predictable freshman year in college - Study Hall Rat, and let him know he won't have a car there either.
It's hard to let your bright son learn some difficult lessons, but, oh well, that's life. I am sure he will be a fast learner
It will be out of your hands next year , and the year begins just 4 months after his graduation from high school. Mine as well get tough right now. Just my two cents. Good Luck!
Always let him know he is loved unconditionally, but privlidges (such as cars and all that they entail) have conditions...