You are NOT a bad daughter...on the contrary. You have so much respect and love for your dad that you don't want to say anything to hurt him or upste him. How many people would examine their every word like this? You are a very special Tzaddekas Dalia...please don't think otherwise! And your father loves you....yet you are the "enemy". You are right and telling him the Emes (truth). Sometimes we can't see the Emes. It is too difficult for us. It is also difficult for a grown man to change his ways. There is not too much we can do to change other people I find. We can only do for ourselves. HOWEVER what we say to a person always sticks with them. Your words may make your father furious for now. But one day they may just seep through and he might change his ways.
I am thinking of you and your dad...I know it will somehow be okay...... *hugs*