Hi OP.
My Dad was taken into hospital just after Christmas for a hip replacement (had a broken hip for a few months, just didn't know about it!). The operation went without an issue, but then on the 3rd day of recovery, his kidneys began to shut down due to the mix of drugs from the surgery and his cancer drugs. He then fell asleep and didn't wake up after that and died on the 6th. Quite a shock to the family, we knew his cancer was advanced but the doctors said he'd still be around for at least a year if not a fair while longer.
It's awful, losing your father. The worst thing that has happened to me.
My words to you won't be 'sorry for your loss' or anything like that as ultimately they don't really help - something a friend of mine told me when I told her about my loss as her father had died last year.
However, just remember to greive. You'll need to be strong for the family, and help them get through this sad and terrible time. But remember to take time for yourself. If that's on your own, or with people, or with a bottle of whisky and your thoughts then it's all fine (I picked the latter). Remember the man for who he was and try and get through the arrangements in a way that would make him proud.
Just take care of yourself and your family and hopefully, if you're like my family and I then you'll be able to have a good laugh and some nice times in between the sadness during the coming days and weeks.