I'm doing private lessons for various programming subjects. One of my students has a tendency to send multiple messages if I don't reply at once, likes emphasizing his effort even though I tell him that mostly only results matter and noone will care enough to look at his effort. He's 25 years of age.
I've usually just shrugged it off, but a few days ago an incident occured. I was supposed to reschedule a lesson with him due to a meeting I could not reschedule, for official employment reasons. What happened was that he got into a fit, saying how he needed my help and that he's gonna fail his class without me etc. He even gave his mother his phone so she could call me, even though there was nothing he or his mother could do to help me reschedule that meeting and I made that perfectly clear, even though they offered reimbursements.
How do I make him realize I don't care about his grades and his efforts if he can't handle most of the curriculum on his own, and I'm here only on business and not to make friends, and that I don't want any further commitments beyond that?
Edit 1: as with all my other students, my tutoring was always on a one-lesson basis. I can help with a certain assignment, homework, or lesson, and we can arrange, but not necessarily, another one, may it be for the same assignment/lesson/whatever or for a completely unrelated one. I've never had any obligations outside of my work hours.