• If my father makes a mistake am I not permitted to correct him?
• There is much discussion in poskim as to the parameters of this halacha.
• The Prisha (YD 240:3) writes that it is only forbidden to contradict a parent if one does
  not have proof.
• You should not argue with your father just because you feel that he is wrong.
• But if there is definite proof that a mistake was made in religious matters, then one is
  obligated to point this out.
• The Gemara has many examples of Tana’im & Amora’im who disagreed with the rulings
  of their fathers because they had proofs to the contrary.
• Pischei Teshuva (YD 240:1) writes that if a father & son are studying Torah together,
  the son may argue with his father even without a proof, since this is the method of delving
  into Torah.
• The Be’er Sheva (Sanhedrin 110a) writes that it is permissible to disagree with a parent,
  but it must be done in a respectful manner.
• Not contradicting a parent means, one should not say, “Father, you are wrong.”
• Rather, one must always speak to a parent in a respectful manner.

I did not show proper honor to my parents. Must I ask them forgiveness?

• One who transgresses a mitzva “bein adam l'chaveiro" (between man & his fellow man)
  must ask forgiveness both from Hashem, for not heeding His commandment & from the
  friend that was wronged.
• For a mitzvah “bein adam la'Makov" between man & Hashem), one need only ask
  forgiveness from Hashem.
• The Minchas Chinuch (Mitzvah 33) is uncertain if honoring a parent is a mitzvah
  (“bein adam l' chaveiro)
• On the one hand, a mitzvah of "bein adam l' chaveiro) generally applies equally to all
  people & perhaps the extra honor that is due to a parent is a mitzvah "bein ada la Makom"obligation to the parent.
• The Minchas Chinuch above leaves the question unanswered.
• Elsewhere (Mitzvah 364), the Minchas Chinuch writes that honoring parents falls
  under the category of mitzvos(“bein adam l' chaveiro).
•  In practice, if one did not show proper respect, one must ask forgiveness from their
  parents (Yalkut Yosef, Kibud Av V’aim1:12).
  

My father asks me to pass the plate of cookies, but I know that his doctor instructed him to watch his sugar.
if I don’t listen to my father, he becomes angry,
& says I am being disobedient.
Must I listen to my father even though I know it is bad for him?

• Sefer Chasidim (234) writes that even if a parent orders a child to bring food which
  endangers the parent & swears that they will otherwise never forgive the child, the child
  may still not bring their parents something which might endanger them.
• The Mahari Malcho (cited by the Birkei Yosef YD 240:15) deduces from the wording
  of the Sefer Chasidim that only if the food presents a potentially life-threatening danger
  must the child not listen.
  
• However, if the food does not present a life-threatening danger, even though it is harmful
  for the parent, the child must listen.
• However, Yad Shaul (240:11) understood that the intent of the Sefer Chasidim was to
  forbid serving any food that is harmful to the parent.
• Sefer Kol Gadol (54) also agrees that the child should not listen in any case of harm.
• He explains that the child is not violating kibud av since the intent of the child is not to
  disobey his father, but rather concern for his father’s well-being.

Is there a mitzvah to honor step-parents?

• There is a Torah obligation to honor a step-mother or a step-father so long as one’s
  father or mother is still alive.
  
• Once the parent passes away, there is no further obligation to honor the step-parent.
• However, the Gemara (Kesubos 103a) relates that Rebbi Yehuda HaNasi instructed
  his children before his passing to continue to show honor to their step-mother & this is
  the accepted practice of all G-d fearing individuals even though it is not a formal
  obligation (Aruch Hashulchan YD 240:43).
  
• The Birkei Yosef (YD 240:16) writes that one is obligated to show honor to their step-
  mother even if their birth mother objects.
• Honoring their step-mother is a means of honoring their father & the birth mother’s
  objections do not remove this obligation.
• However, Halachos Ketanos (1:28) writes that if there is a question of who should be
  honored first (e.g one’s mother & step-mother both ask for a drink of water), one is
  obligated to honor one’s mother first.
• Though they are both Torah obligations, the honor that is due to a parent is greater
  than that due to a step-parent.