You should celebrate it because you survived it. And you became stronger because of it. And no matter what he says, you should know, judging by your picture that you're a grown man, you didn't really kill your Mother. Things like that sadly happen, without rhyme or reason.
My Father sucked too. He did things that... a father should have never done to a little girl, let alone his little girl. And on top of that he would beat me and my Mom.
But I refuse to let him dictate my life now. He's dead, and I'm not. And I know not all men behave like he did, that there are loving caring men that don't do the things that he did just because they love you. What he did wasn't out of love.
So come have a cupcake, because we survived our asshole fathers.