It is very difficult for you. You don't want him to die, but the waiting is so hard. Take a deep breath, open up the photo albums and remember the good times. When his breating has slowed to 6 -8 breaths per minute the time is coming. Look at his hands and feet, they will start to discolor and turn bluish grey. The discoloration may go up the arms and legs a little bit. Then the time will be soon after that. I am so sorry for your pain. It's hard to do what you are doing. You and hold his hand and whisper to him you are there and it's ok for him to let go. My prayers are with you.