ed34, I was thinking the same thing and hoping it's what you suggest -- that they have him sedated, and he'll come out of it.
I am wondering if he was kept in heavy sedation, or if it is actually a coma. I am very shocked that if a coma, they haven't given the family any details?
What it indicates depends very much on how the surgery went and why he is not yet awake. I think that what the family should make of it really depends on the details. For a coronary artery bypass, I would not expect this outcome, but what explanation has the doctor given you? In your situation, I would be concerned, but I might not be AS concerned if there were a good explanation.
Has a medical professional actually stated the word COMA?