She has a picture of him. She's made a video asking if anyone recognizes him.
http://www.news.com.au/entertainment/tv/after-a-fruitless-search-on-who-do-you-think-you-are-toni-collette-asks-the-public-to-help-find-her-grandfather/story-e6frfmyi-1227479063433
http://www.news.com.au/entertainment/tv/after-a-fruitless-search-on-who-do-you-think-you-are-toni-collette-asks-the-public-to-help-find-her-grandfather/story-e6frfmyi-1227479063433