My father had by-pass surgery on the 19th of January and valve replacement. He has been on the ventilator twice since surgery due to different issues. We know he is tired, however is it unusual to keep eyes closed all the time and sleep most of the time. He will respond some times to us but is sleeping majority of time. If he is awake at all it is maybe 5 to 10 minutes at a time. No one seems to be able to help us with this issue.