I had heard that when there is a conflict of requests between father and mother, a son should defer to his father first.
Does this rule apply if the father is dead but the mother is still alive? I.e., prior to his death the father wants his son to practice a certain minhag but the mother doesn't want him to. Does he always have to defer to his father's wishes, or does it vary on the type / category of the situation?
Within all this, I am assuming that the son is required to honor his father even after death. If that's incorrect, please inform me as to why. My premise would be wrong, then.