date night party

So my bfs frat has a date night party next week. I will be out of state and cant make it. He for some reason wants to still go and from what hes said to me sounds like he wants a date. Okay i understand him wanting to go and all but he doesnt need a date. Theres this girl who i know he would ask because she will be there anways(sorority) and i do not trust her at all. Also that its at my bfs house. Weve been dating awhil. Do i let him make the calls and hope he does what is best for us? Im terrified he will take her and not tell me.  What can i do?!