Is My Child Old Enough to Spend the Night Away from Home?

My 2nd grader brought home an invitation for an overnight slumber party during the Christmas holidays to celebrate a classmate's birthday. He has never spent the night away from home, except with grandparents or at one particularly-close friend's home, so I worry about whether he is old enough to spend the night away successfully. I want to save him the embarassment of a middle-of-the-night "I want to go home" bout or other concerns. What do you think?