Is it bad for students sleep to take 2 hour naps every day?

Yes and NO: It suggests the student is not getting enough sleep at night. Sleep is very important to perform well in the day time. When you require naps it is probably due to poor sleep. About 9 hours is a good amount of sleep every night. If he is getting 9 hours then the quality of sleep may be a problem. Talk with your doctor about sleep problems, may need sleep study.