| Quote #1
[Dmitri] was stunned, suspected a lie or a trick, was almost beside himself, and, as it were, lost all reason. This very circumstance led to the catastrophe. (1.2.2)
Dmitri is so offended and wounded by his father's betrayal that he almost loses his mind. This brings up the question of whether the murder of his father was justified, as his defense attorney will argue much later in the novel.
| Quote #2
But Dmitri raised both hands and suddenly seized the old man by the two surviving wisps of hair on his temples, pulled, and smashed him against the floor. (3.9.18)
The complete lack of any family feelings is shown here as Dmitri violently lashes out against his own father.
| Quote #3
"Viper will eat viper, and it would serve them both right!" (3.9.37)
Ivan here rejects any responsibility for the deteriorating relationship between Dmitri and his father, and by extension rejects any family obligation whatsoever.