Can you cancel training if it was OPTIONAL?

I am going to visit my bf next week, turns out he has drill so he’ll be too busy for 2–3 days. He convinced me to extend my trip two more days so I did. He just found out that he has two day training in Philadelphia the SAME day I’m leaving…so he’ll be leaving for the airport in the MORNING and I’ll be leaving LATE at night.

I won’t know anyone and I’ll be sitting at the airport for several hours waiting to be checked in.

If my boyfriend had the OPTION of going to train for two days…can he have the option of backing out? Or is it too late?? He still has 2–3 weeks left to tell them “no” if he can. Please let me know.