it depends if they have just fainted or if they are going to be out for a while, it also depends on the situation. If the person faints you should rub their hands and arms and try to get circulation running. also they should be on a relatively flat surface and after they wake up, give them some food. Nothing too heavy, maybe something like crackers, and also something to drink. Something that has suger in it so that their glucose levels will stabilize.
The same as a conscious person. Just no water.
If they are unconscious and breathing, nothing will happen. If they are unconscious and not breathing, they will die.
breathing
Could be. Breathing is not a response. A person who is unconscious would be unresponsive and still breathing.
CPR should be performed if a person is unconscious and not breathing
Up to (but no longer than) 10 secs
So you don't stop breathing even when you are asleep or unconscious.
First perform an Initial Assessment. Open the airway, Check for breathing, if there is no breathing give two rescue breaths. If the rescue breaths go in and make the chest clearly rise check for a pulse. IF there is no pulse begin CPR.
Passed Out But You Are Still Breathing
When a person has stopped breathing and can not breathe on his own, rescue breathing (or Mouth-To-Mouth Resuscitation) is given to try and saved the persons live (in addition to CPR and/or defibrilation).
Make sure that it is necessary. If the person is unconscious and breathing, CPR is not indicated; you may do more harm than good.
If a drug overdose is discovered or suspected, and the person is unconscious, having convulsions, or is not breathing, call for emergency help immediately
If the person finding the unconscious person is trained in First Aid, then use your skills to check for breathing and react appropriately, removing the blockage if applicable and beginning CPR. If two people find someone unconscious, one person stays with the unconscious person and the other goes to call 911 for emergency assistance. Even if only one person finds someone unconscious and knows First Aid, 911 must still be called because CPR is only designed to keep the heart and brain full of blood while EMT is making their way to the person.