Bachlor Party

I am furious with my fiance`s brother (the best man), I have been asking him for months if he was going to invite my father to the bachlor party and he said he had to check with my fiance..never giving me a straight answer. I only asked because my fiance and my family are close and have known each other for many years and my father mentioned to me he wanted to go. Finally when I found out people had been invited I asked the best man about it and let him know it would mean a lot to me if he invited my father and that my fiance wanted him there( which he does) and he said it wasn`t tradition to ask my father, yet thier father was invited and is going!!! I even explained that my father would not be able to attend but the invitation alone would mean a lot to me and my father and he still stuck to his answer of not inviting him. Yet thier sister is a bridesmaid and invited their mother to my bachlorette party.