From our extensive experience with this, his chances are 500 % Better if the Family Stays at the hospital and see;s to it he gets his meals ( HAND FEED HIM, DO not RELY ON A NURSE TO DO IT)..
they MAY NOT LIKE IT MUCH, BUT YOU CAN REMAIN IN THE WAITING ROOM AND VISIT HIM AT INTERVALS NOT SCHEDULED..
Biggest thing is to make the Dr. understand you Expect him/Her to give him every chance possible..
Agreed, 24-48 hrs is pivotal, but my Father was in Coronary Care steady for 5 Months, Coded Blue un-counted numbers of times .. On an Intra-aortic balloon pump for 30 days..
Clots from that caused him to loose his legs above the knees, BUT..HE DID Survive and had 6 pretty good years..
Pray and Believe in Miracles...don't "Expect" them, Believe in them..they DO happen..
Hope he surprises you...!! BEST Wishes to you, Him..