If someone has passed out drunk the best thing to do is to put them to bed and let them sleep it off

The amount of alcohol it takes to make someone pass out is close to the amount that will cause death. Their body will continue to process any drinks taken just before they passed out, possibly increasing their blood alcohol to the point that they may go into cardiac arrest. Also, if they throw up while passed out they could choke and die. Do not leave someone who has passed out alone. They need to be watched over until they have returned to consciousness so that medical attention can be sought if they get into difficulty.