What is the ruling on dealing with a difficult mother who refuses to obey and responds with shouting despite attempts to appease her?

It is advised to adhere to obedience to your mother, to be patient with her, and to strive to please her, based on the words of the Almighty: "And your Lord has decreed that you shall not worship except Him, and to parents, good treatment. Whether one or both of them reach old age [while] with you, say not to them [even] 'uff,' and do not repel them but speak to them a noble word." Allah has commanded to lower the wing of humility to them and to address them with a noble word in their old age, a state that requires dutifulness due to the parents' weakness. Thus, there is no escape from obeying them in ease and in hardship.