How can I ask her?

Soo this Saturday I have my brothers first communion and we’re going to mass for it ofc and then brunch after. My mom suggested that I invite my best friend but I wanna invite my guy friend. Here’s the thing: him and I like eachother and she knows that (he’s hung out w us before but w my best friend and my family) but she’s always iffy on me wanting to hang w him. I mean it’s not like we’re going to the movies we’re going to mass so it wont be like a date. How should I ask her?