Answer in your head first
Then reveal it.
You state a limit once. It is met with an accusation that you have abandoned your parents. What does this lesson say to do with that?
Nothing, and that is the whole discipline of it. The accusation is a bid to reopen the debate, and answering it is the step that keeps the engine running, however reasonable the answer would be. It does not mean going cold or silent. Kindness in speech, presence and help all continue, and the limit continues at the same time. If the accusation is a religious one about severing the tie, that is a question for a scholar who knows your case, not for a family argument.