Health Hazards-Must one listen to his father if he asks him to feed him a food or beverage that is against the doctor’s orders due to a health condition?
A child is not obligated to listen to his father regarding a matter that is damaging to his health. This applies even if the father threatens not to forgive his son, not in this world or the next world if he does not comply with his wishes. [This applies even if the matter is not lethally dangerous for the parent but are simply damaging to his general health. Some Poskim, however, rule that this only applies if the matter is possibly lethally dangerous for the parent. If, however, it is not lethally dangerous then the child must obey his father’s instructions even though the matter he is asking for is unhealthy for the father. Furthermore, the above allowance for the son to disobey his parent only applies if the doctor gave a personal directive to the parent to avoid the matter based on their medical history and condition. If, however, the doctors did not personally instruct the parent against it, then the son must apply to his parents’ wishes even if it is contrary to general health directives for the public. Thus, if one parent asks from his son to place sugar within his coffee, the son may not refuse to do so on the basis that sugar is not healthy for the body absent of a specific doctor’s orders for his parent.]
 Sefer Chassidim 234; Beis Lechem Yehuda 240:8; Birkeiy Yosef 240:8-10; Mahariy Molko 113; Beir Moshe 6:160-9; Yalkut Yosef Kibbud Av Vaeim p. 385; Pesakim Uteshuvos 240:14; Encyclopedia Talmudit Erech Kibud Av Vaeim Vol. 26 p. 385-386 footnote 214
 Leket Yosher 2:37; Maharam Ben Chaviv Kol Gadol 54; Kneses Hagedola 240:33; Beis Lechem Yehuda 240; Aruch Hashulchan 240:41; Encyclopedia Talmudit ibid footnote 215
 See Birkeiy Yosef 240:8-10; Bris Olam of Sefer Chassidim ibid; Mahariy Molko 113; Encyclopedia Talmudit ibid footnote 216
 Rav Elyashiv in Mivakshei Torah 20 p. 151; Yalkut Yosef Hilchos Kibbud Av Vaeim 7:16 in name of his father Rav Ovadia; Beir Moshe 1:60-10