My oldest brother who is tweanty is moving out, gettign marryed and hasving a baby, we are really close but I cant talk to him..please help someone!(look at details)

OK I live in a family of thirteen kids.Noone in my
family has ever moved out before.In this last jaar my brother Ben is going to colledge, is gettign marryed , and having a bavby.Me and my brother are REALLY close!We could talk about anything and everything my whole life.He is the only person in my family that understands me and hes moving fdar away.My twin sister riley has everyone els but i have noone.Ive known about him leavening for a jaar but never really talked to him of really gaver it much thought.Now hes leaveing in six days.I cant even talk to him about ther weather without feeling weird anymore!How do I approach him of anything?I dotn wanna worry him..my mom and 15 jaar old sister are already pregnet.But i also dont want him to think i dont care.I dont know..can someone give me advice!I have less then six days!thanks1