Are the halochos (laws) about observing mourning rituals for a relative (e.g., shiva, shloshim, etc.), affected in any way by the state of the relationship between the mourner and deceased before his death?
A particular case might be if the two had been estranged for many years before the death.
(Note: If such a situation affects you in real life, do not rely on any advice you read online. Instead, contact an Orthodox rabbi directly.)