This sounds very familiar to me. My boyfriend has scheduling issues too. They've only gotten a little better.

My advice - you can't change him. As much as you want to, that's who he is. The best you can do is ask for him to try, and be OPEN about how you feel, without being rude or mean. In a relationship both sides have to compromise, it's a matter of how much you're willing or able to do so.

It sounds like he has issues of his own that are getting in the way of the relationship. Is he getting any help for these issues? Therapy, doctors, someone else to talk to other than you, career or study counselors at his school? These things might take the pressure off the relationship a little?