The friend who makes sure everyone has a ride home is the leader of the night, whatever anyone else thinks.

Whoever checks that everybody got home is doing the one job that night with real consequences attached. It is unglamorous, it goes unmentioned, and it is the reason the evening ends well rather than badly. Nobody will thank you for it, and whatever anyone thinks the hierarchy is, that is the person holding the group together.

Be the one who counts heads and knows who is walking. Ask the quiet question about how somebody is getting back. It is the least impressive and most useful thing available to you.