I dont want to rain on your parade. However, there is no way in hell your friend is attending a Marine Corps Ball if hes still in Boot Camp. BEST CASE scenario, hell be washing dishes and taking out trash while his Drill Instructors make up him do burpees in cooking oil. I would ask him three questions.
When do you graduate boot camp?
When is the ball?
Where is the ball?
If the date for question one is after the date of question two - do not go. I get the impression he doesnt know what hes talking about. Which is ok, hes probably just being overly enthusiastic right now. Id hate for someone to make long term plans for something that wont ever materialize or end up being a complete nightmare. There are some salty ass Marines with more experience than me on here. Hopefully they chime in. I didnt pick up on this detail initially.