Joseph and Forgiveness

Rabbi Sacks credits Joseph with being the first person in history to forgive as we understand the word. Did Joseph forgive his mother-in-law and would be seducer on the same grounds that he did his brothers?

I think that If indeed Joseph did forgive her, the Torah does not say so explicitly, as the Torah says the greater novelty: he forgave his brothers. I think it's much harder to forgive family then strangers. You expect more from family (especially from Jacob's children) and the pain caused by family is therefore much greater.