We honor them by insisting that they get the professional help that they need, before they have anymore contact with us & our family members.
Would the Catholic Church agree with that? Google shows a lot of articles about Catholicism and narcissism, but I don't know which ones are official or officially endorsed.
ETA: Based on the Mormon answer provided (by JBH, iirc), it seems the answer is likely
In general, yes, but the precise actions to be taken during estrangement or steps to be taken to become estranged or, in the first place, whether or not to become estranged must be decided with advice from a religious or mental health professional/s such as priests, psychologists, psychiatrists, etc.
Probably yes, but definitely seek professional advice.
My guess then is that this question instead falls under a broader range of questions to which the answer is either of the above. What range of questions could this be? I'm thinking now of some church document or section entitled 'On matters pertaining to mental health, etc'