[Doubtful2007]

Hey I might be commenting a little late on this so I hope everything worked out but if nothing has happened yet here's my advice.

I think if you like this guy, and as you stated he likes you back, I think that you tell his sister first. Bring it up plainly and clearly but don't overthink it. say something along the lines of 'hey I need to tell you something. I think your brother is kinda cute and i think i'm gonna ask him out' (or ask for his number, or anything in between those options.) once you have told his sister tell him. Don't overthink this either. He likes you so go get him. If there is one thing a guy loves its a girl that chases him somewhat.

You also mentioned you go to a youth group. So pray. Gods plan is gonna work out no matter what it is. So follow him and you'll be fine.

You got this. Be confident!

(Sorry I didn't see the "female advice preferred tab" thats mb)