Hey Shannon,
I am really sorry to hear of your situation. This is one of my biggest fears and I hate that anyone has to go through with this. However, even though this is tough, try to focus on what will be gained in the future. It is sad to think that we may lose those we love, but we can't live for their sake. WE need to be happy as well. And by exploring and realizing our true potential there is a lot of happiness coming our way.
As for your father in general, give it time. Most parents have a difficulty grasping this and react out of shock. Sometimes, they try to control the situation with fear and threats. But, if you stand your ground and show how sincere you are, he may very well come to accept it in due time. I know this happened to many before, so don't lose all hope.