Very sorry to hear this - can't really offer any help but did not want to ignore this. My way of coping with most things is to find out as much as possible and do everything possible to make sure the other person is getting the best possible care etc. You will get through this and it will have meant a lot to him to have you there today.
So sorry to hear about your dad. That's such a tough situation to be in. All you can do is be there for him and be there for your family. And spend time remembering all the good times you had together. X