no trouble going to sleep, can't wake up

My boyfriend has no trouble going to sleep. In fact, he can fall asleep within one minute after texting me. Every morning, i wake him up by giving him morning calls. But he just doesn't wake up to my calls nor the many alarms he set the night before. No matter how loud they were. It was so bad to the extend that I had to miss call him more than a 100 times before he finally wakes up. Any sound doesnt wake him up unless you shake him. Even as so, I still have to shake him for about 5 minutes then he will wake up. He is always late for school and this is beginning to irritate me. I can't seem to find a way to help him to wake up. What do you think ?