Answer
Stories about the filial piety of a non-Jew, Dama son of Netina, are offered by the Talmudic sages (Kiddushin 31a) as a model in response to the question “How far does the honor of parents extend?” In one of the anecdotes, “Dama was wearing a gold embroidered silken cloth and sitting among the Roman nobles, when his mother came, tore it off from him, struck him on the head, and spat in his face, yet he did not shame her.”
Another story told in the same discussion shows us Rabbi Tarfon crouching down for his mother to use his back as a stepstool to get in and out of her bed. When he told others about this, they were unimpressed and asked him, “Has she thrown a purse before you into the sea without your shaming her?” That, they were telling him, is the standard to which one must aspire.
Yet In talmud Tractate (Kidushin page 31 b) we find that Rav Asi saw that his mother lost her mind so he left her alone.
The Maimonides writes in the laws of mamrim chapter six halacha ten that if one’s parents loose their mind one should nonetheless try to act with them properly until they’re situation improve and if one cannot because they have become to irrational one should then leave them and have others take care of them in his place and so to the Shulchan Aruch (יו”ד סימן ר”מ סעיף י’ ) rules that if it is to difficult to take care of the parent one can give them to the care of someone else.
Although the Maimonides seems to in line with the Talmud that Rav Asi left his mother Yet a explanation of the Talmud given by the bach (yoreh deah siman 240 sief katan 12),
Rav Asi left his mother not because she was crazy rather because she was old , bad hearted and was demanding of him in a manner that he couldn’t fulfil her requests.
yet if she is not sane ,unstable then the child is to stay with the parent care for them and to not take to heart what they tell him, yet Contemporary Achronim point out that today in many situation parents with a difficult situation institutions will be able will be able to care of them better then their children.
So according to the bach we see that one can leave problematic parents .
Some Achronim add yet another reason for exempting a child from the obligation of honoring abusive parents . Asserting that there are limits to how much a person is allowed to spend in order to fulfill a positive commandment—no more than one-fifth of one’s monetary assets—they argue that emotional distress and psychological consequences are excessive personal costs that free one from an obligation.
In addition, children are not obligated to honor parents when the expressions of that honor support sinful acts. If by honoring the parents one causes them to fight with the child one should avoid bringing them to such a situation of sin .
In conclusion one can be lenient and avoid honoring parents in such situations yet one should be very careful and best to take professional advice on how to honor even in such situations.
Rabenu Sadyah Gaon (Rabenu Bchyee shemos chapter 20 verse 12) explains that due to the fact that in some instances it will be difficult for a child to honor his parents therefore the torah gives the reward of arichus yomim for one who goes out of his way to honor them and takes care of them although it is difficult merits to a long life (and chas vshalom the other way).
