Respecting the elders is obligatory, but some people have some mental problems, some more and some less. If a real mental patient, due to his mental state, says useless and bad things that can or will have bad results, not only in worldly matters but also (lead to a) sin, both for him and others, then to avoid such consequences, is it permissible to speak with him in a bad manner, i.e. loudly, or to rebuke him, provided that it is only to the extent of necessity? Can you please tell me the correct behaviour regarding that with a father as well as a grandmother?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.

There is no doubt that respecting and honoring the elderly is Islamically ordained, as the hadeeth reads, "He is not one of us who does not have mercy towards our young and does not honor our elderly." [At-Tirmithi] Abu Daawood narrated the same hadeeth with the addition: “‘…and knows the right of our elderly.’ Ibn 'Allaan in Daleel al-Faaliheen commented on it saying: "He is not from us, i.e. from the people of our Sunnah, guidance and way.” 

Ibn Muflih said in al-Furoo’, “The scholars of the Hanbali School stated that this wording, which is the saying of the legislating Prophet : ‘He is not one of us who said or did such and such,’ necessitates prohibition, and some of them considered it a grave major sin.”

However, this respect does not mean not objecting to him, as the scholars stated that if a mad person does something that requires objecting to his act or statement, then he should be objected to. Ibn Qudaamah said in Mukhtasar Minhaaj al-Qaasideen while clarifying the conditions for the one to whom we object, “The third pillar: the one to whom we object, it is enough that he is a human being, and it is not a condition that he is a Mukallaf (a person who is competent for religious assignments), as we have already clarified before, that we object to the child (minor) and insane.”

The person who is not as such [i.e. who is neither a minor nor an insane person], then it is more appropriate to object to him, but without rebuking or reprimanding him as per the etiquette of prohibiting evil; that it should be in a gentle manner; this is even confirmed in regard to the elderly, and especially the parents. Al-Qaraafi said in al-Furooq, “‘The parents should be ordered to do good and prohibited from doing evil,’ Maalik said, and one should lower the wing of humility to them out of mercy to them.”

The book Al-Aadaab Ash-Shar’iyyah authored by Ibn Muflih reads:

“Chapter on ordering parents to enjoin good and forbidding them from doing evil: Ahmad said in the narration by Yoosuf ibn Moosa: One should order his parents to enjoin good and forbid evil, and he said in the narration of Hanbal: if he sees his father doing something that he dislikes, he teaches him without violence or abuse, and he should not speak to him in a harsh way, otherwise he should leave him because a father is not like a stranger [a person who is not a relative].”

For more benefit, please refer to fatwa 247126.

Allaah knows best.