How do I deal with my narcissistic mother that lives in NH and I live in FL? I wish I could go no contact, but not as she's 84?

Is your Mom able to be independent? Does she live in her own home, Assisted Living or Long-term care?

If she is independent and able to do for herself, I would not worry. If she is in an AL or LTC she is safe and cared for.

You deal by setting boundaries for yourself even if she tries to step over them. If you call and she gets started, tell her you will call her back when she is in a better mood. You get treated the way you allow people to treat you. Be happy that you do not live near her. And do not promise her anything. You should never live with her or her with you. Your in control, do or not do its up to you. Mom needs you more than u need her.

Well first be grateful that you live many states apart. And what does her age have to do with not being able to go "no contact?" Do you feel that you have some type of responsibility to her? You don't you know?
Just because she is your mother doesn't mean that you owe her anything. It is entirely up to you as to how much time and effort you want to put into your relationship with her.
You again have the advantage of being miles apart, so if you decide that you still want to be her advocate(from afar)well so be it. And if you decide that you've had enough of her nonsense and want to go no contact, well so be it.
Only you can decide what you will tolerate and what you won't.
You have to do what is best for your mental health, not your mothers.

Does she live alone? Does anyone else check up on her? Does she need help?
Perhaps she needs assisted living ? If she was being looked after in assisted living, then you could step back knowing that she is being cared for. You could call the staff to see how she is doing.

If she is of sound mind and needs no help , go no contact if you like.

Im in same boat. People don't understand narcissitic personality disorder can take the forms of verbal, physical, emotional abuse then add dementia and alz. I'm an only child so I opted for assisted living and have been very clear about the situation.

She is 84 and could live at least ten more years. Also being 84 doesn’t entitle anyone to perpetual contact, care, hovering, worry, or popcorn on Friday nights.

What encourages help for an 84 year old person is if they’re being pleasant, thoughtful, kind, undemanding and appreciative. If your mom isn’t any of these qualities, you have the right to pull the plug.

Abuse from others is never okay. Next question, please.

Send a lovely card. Make a weekly call. Send flowers, candies, cuddly bear, whatever. Then move on with your real life.