Simon Dedalus was a major figure in A Portrait of the Artist as a Young Man, and he appears frequently in Ulysses. He grew up in Cork, and was a fairly successful man until recently, when fell on hard times. In Portrait, we get a glimpse of him as a strong Irish nationalist and a passionate sympathizer with Charles Stewart Parnell. At the start of Ulysses, we find Dedalus in mourning for dead wife, Mary. He has begun drinking even more heavily than he used to and his family life is in utter disarray. It has been noted that Simon is modeled closely on Joyce's own father, John Stanislaus (Ellmann, James Joyce, 11).
Simon is critical of Stephen's lifestyle, and laments the fact that Stephen abandoned medical school to become a struggling artist. The criticism goes both ways, however. Stephen clearly feels estranged from his family, and in "The Wandering Rocks," we get a glimpse of his sisters, who are living in utter poverty because Simon spends the little money he has on drink instead of feeding his children. Simon is clearly in mourning for his wife, and when he passes near her grave in "Hades," we see him break down in tears. It is clear, however, that his grief has led him to become overly sentimental and self-pitying.
Despite his faults, it is clear that Simon is a well-respected and connected man about town. At the funeral, other men seem to look up to him, and he becomes the center of attention when he sings Martha at the Ormond Hotel bar in "Sirens." Yet it is Simon's absence and neglect that causes Stephen's feelings of alienation and opens the door for Bloom to become a sort of surrogate father to Stephen.