I am sorry for your father's unfortunate experience. Sometimes unexpected things happen during surgery, and this may be one of them. From what you say, your father's brain did not get enough oxygen for 3-5 minutes. This can cause some brain damage just the way a stroke does, and sometimes, stroke victims experience something called "Pseudobulbar affect," a condition which causes extreme emotional responses to things that are usually just normal stuff.
Please google that term and ask your father's doctors about it.
Hi there, sorry to hear of your fathers experience. Hope all is ok.
Just a question, by any chance did your father have any Kidney issues prior to the surgery. I ask because a close relative had his Aortic valve replaced some years ago and had similar complications. For eight days after the surgery, he couldn't be woken. He began to tremble uncontrollably for a couple of days, still no response. The medics did the CT etc and were a bit baffled. He had been on Dialysis prior to his surgery. Eventually on the 9th day he began to come around, by day ten he was sitting up! I have to say we had been very worried , as i'm sure you are now. Please god he will recover quickly. It seemed to be caused by some sort of reaction to the anesthetic.