O's dad made it through the surgery. He had a ruptured abdominal aorta. It was the 'best sort' of rupture, and the doctors were able to repair it. He'll be in the hospital for 7-10 days, maybe more. Recovery will take months. The next danger is heart attack, but he's in the best place he can be.
Thanks everyone for your kind thoughts and words. This is a tough time for O, but he is shining through it, like I knew he would.