Twice I've had people not listen to me telling them that I didn't want to do anything for my birthday. There have been parties, and I've had to be gracious and go along with them, because it is hard to storm out of your own house at 8 pm and find anything to do for hours until everyone leaves.
So I vote don't do anything at this dinner. I was not happy, to put it mildly, with the people who forced the parties on me.
However, you could call your father and tell him that you would like to do something, just the two of you, to celebrate and commemorate this milestone birthday. Offer him a few suggestions--a birthday lunch at his favorite diner, a fancy birthday dinner, an afternoon fishing (or whatever his favorite hobby is), a day where you visit him and take care of all the little things around the house that he can't get to anymore, driving him to visit an old friend who can't get around much. He'll either pick one, or he'll tell you that he really doesn't want to do anything. And then you can rest easy either way, because you will be doing what he wants for his birthday. Whichever way it goes, a card should be okay, as well.
I discovered that my dad really liked to be taken out to breakfast for his birthday, at a coffee shop where a lot of his cronies hung out. He not only got time with his children, but he was able to show them off to all his friends. Not a big deal for us, but it meant something to Dad.