Why tell her now? If he just passed away, isnt she going through enough? Later, like when she's not still grieving, you can let her know that her daddy didn't help make her, but he was a daddy in the only way that counts... he loves/loved her. Good Luck to you.
Just let her know later when she is not hurting. My real dad committed suicide last year, and then people started putting all this other stuff on me and it just made it worse, so let her heart heal a little before you bring out something big. And i agree with ajc77 you can tell her that even though he didn't make her he still loved her as his daughter so he still counts as her daddy.
ajc77 is right. What until the moment is right to tell her. Don't do it now. I know if it were me that would make loosing my daddy all the worse. I found out not that long ago that the man who I have called dad for 16 years was not my biological dad. It is a man I've never met in my life. It is a man that I haven't ever talked too. Everyone says I look just like him but the truth is nothing will change who my daddy is, my true daddy. I love him. He has been there through it all. Even though he knows he's not technically mine, he's still here and still wants to be in my life. She deserves to know. No matter what age she is. I just think his love for her will be enough prove that even though a piece of paper says she's not his. He truly will still and always be her daddy. And she will forever be his little princess.