My 81 Year Old Father Had Quadruple Heart Bypass Surgery.

My 81 year old father had quadruple heart bypass surgery. The surgeon said so much calcification in aorta that it apparently broke off during surgery and caused a massive stroke. Cat scan today showed massive stroke with severe swelling in left side and pushing right side of brain. He has been placed on saline solution to reduce swelling and doctor said prognosis extremely poor. All his other vitals are perfect. I'm believing in a miracle and while he is unresponsive most of the time with fixed eyes, he often responds to our requests to move his legs, squeeze our hand with his and blink his eyes. How long do you think recovery could take?