Response

Yes it is ethical. It is ethical because it is his own private stuff. People don't have to tell them what to do with his e-mail because it's his responsibility.  He needs to know what is right and what is wrong. So it is his own private stuff it's nobody else. Because it is from home it is not anything bad from school. He is just inviting them to come and have a BYOB  party to have fun and relax. What's the big deal about having a party it's at his house not during school time.