Is it permissible to disobey a father or grandmother suffering from a mental illness in matters that may worsen their condition?

A Muslim is not permitted to harm themselves or others, and this is a legal principle derived from the Prophet's saying: "There shall be no harm or reciprocating harm." Obedience to parents is obligatory in permissible matters, even if there is hardship in them, as long as it does not result in certain or predominant harm to the parents or the child. If harm results from it, the obligation ceases. It must be noted that the harm must be certain, that abandoning obedience should not lead to greater harm, and that the harm must be apparent and established. The duty towards parents is to be gentle, to treat them kindly, and to care for them in their weakness.