Here is an interesting article on siblings, with Freud as an example on unconscious feeling's towards one's siblings.
The role of siblings in mental life may have first been underemphasized by Freud, who may have had his own reasons for such downplaying. For example, Freud as a child had a private bedroom filled with books while all of his siblings lived together in one other, crowded room.
And in another place:
As noted by the authors, the index of the complete standard edition of Freud's works has no reference to sibling (although Siberia is referenced).
Freud was a man unusually preoccupied with death. His concern stemmed partly from the painful heart attacks he suffered when he was still in his 30s. The ailment, never definitively diagnosed, was the cause of continuing anxiety. Indeed, Psychoanalyst Ernest Jones, Freud's most authoritative biographer, thought that the symptoms themselves were due to "anxiety hysteria," while Schur believed that Freud may actually have had a coronary thrombosis. Freud was also profoundly affected by the deaths in his own family, beginning with that of his brother Julius when Freud was only 19 months old. When his daughter Sophie died, he spoke of "the monstrous fact of children dying before their parents." On the death of Sophie's son at the age of four, he mourned: "Everything has lost its meaning for me."
Oedipal Conflict. Yet to Freud, a father's death was always "the most important event, the most poignant loss, of a man's life." His own father died when Freud was 40. The complexity of his grief was related to his work at that period: just after his father's last illness, Freud became aware of the Oedipal conflict and the "ambivalence in man's relationship to beloved and revered parents.