Stop making up scenarios that aren't occurring, then. You asked him why he couldn't do both. He clearly stated he wanted to focus on school, and didn't need the money. How in the world do you turn that into "he can't do it"? You then go on to tell him if he quits in less than a year, he won't be rehired. He clearly stated in the op that he is seasonal, and was offered a position which he isn't taking due to school. Again, where did you come up with this?
You are either have very low reading comprehension, or you are being willfully obtuse.