find my biological grandfather

This probably sounds like a strange one.
My mother was adopted the day after she was born. Two years ago I helped her find her biological mother’s family. But her birth mother died years ago, and my mum’s half-sisters didn’t even know she existed. So it’s going to be next to impossible to track down her birth father.
But I have to try. For many reasons, one of which is that I don’t look like ANYONE in my family. I’m a genetic anomaly. I like to think that maybe I look like his family.
I don’t know. But he’s out there somewhere.
Unless he’s dead. Then I’m screwed.