That must have been really unnerving, sorry you had to go through that. You might consider having a fasting blood sugar test - a really low sugar can make someone difficult to waken.
Just as a precaution, make sure you have a monoxide detector and one for natural gas. This issue is less likely if you had the same problem 20 years ago, luckily.
You were definitely in a DEEP sleep. It is good your subconscious realized your dad and wife were there to wake you if you were passing into an endless sleep. Just part of life, but try to get adequate rest every 24 hour period.
I think if you were particularly tired, exhausted the "dead" sleep is not unusual. If it is chronic you should discuss with a doctor.
You mention shift work, changing when you sleep, that can be very difficult for some people.