Brothers

So my brother is visiting this weekend. Still hasn't bought plane tickets. He just called (at quarter-to-midnight) to ask if coming in around noon on Friday would be ok. Then he asked what my schedule was like on Monday. Since we started discussing his visit, months ago, I've been telling him that Mondays are the only day of the week that I have class, that Mondays are 12 hours days for me, and that if he's going to take a long weekend he needs to take Thursday or Friday and leave on Sunday because I have shit to do. Of course, he's planning to leave 'sometime Monday.' The question is, why do I find it so impossible to just say to him, No, Brad, we've had this conversation, book your flight for Sunday evening, or, though I dislike this option, early Monday morning and I'll drop you off on my way to class? [edited to make sense]