I was in ICU with Mum on and off until Sunday. They had him wired up to all sorts of monitors and pumps for 7 different drugs. He almost woke on Saturday, but he threatened to pull the tubes out so the ICU staff put him in an induced coma. The doctor said all his organs were working well and there was no blood in the chest drains - ie no bleeding on the grafts - but he wasn't recovering as fast as they liked. They put him through a CT scan to see if there was a problem but there wasn't - he was simply not recovering.
On Sunday Dad's condition started to improve so they began to withdraw the medications. As of today the only med he is on is insulin to manage his diabetes. At some point in the next few days he will burn off the sedatives keeping him in a coma and begin to wake.