Dad has dementia, is having nutrition related health problems and is refusing doctor advice. Do I just let it be?

My vote is to let him be.

There are no nutritional guidelines that will cure dementia. There are no medications that will cure dementia. There are symptoms that may be helped by nutritional practices and/or medication. For example, if he had bouts of extreme anxiety an anti-anxiety med may help. If he is prone to dehydration, a larger intake of fluids is a good idea. But his overall conditions? They are what they are, whether he eats well or takes medications or not.

What do you mean by "he refuses help"? What kind of help is he being offered?

I agree with BarbB that it is perfectly OK to call 911 and not to get involved in the ER trip, if that suits you. I caution you not to expect to "teach" him anything by your absence. He won't learn that this is not a good way to get your attention, for example.

I am so very sorry that you are dealing with this challenging situation now, and that you've had a long-term challenge with his narcissism.

You state that your father is unwilling to follow doctor's advice on nutrition and medication. I'd just like to suggest that when dementia is involved, the patient often forgets about the doctor's advice. And even with reminders, they may not be able to keep up with medication regimen. They often forget that they have a medical condition and convincing them otherwise is difficult or impossible. Even if he was stubborn before, the brain damage just keeps them from keeping things straight, using good judgment and even accepting help. That's why there are so many concerned family members who try to help or to get the loved one with dementia to accept help, to no avail. There are no easy answers.

Some people jump in and try to get things under control with legal proceedings, like Guardianship. Others meet the doctor and start using the Durable POA, in order to get the person into a facility or bring outside help into the home. Still, it's challenging when the patient is angry and resistant. I'd consider how far his dementia has progressed and consult with an Elder Law attorney, so you can find out your options and what evidence you might need.

I'm surprised that the doctors from the ER have not reported him to APS for an investigation. Those types of calls are not uncommon for dementia patients who live alone and often precede the need for family or county to step in for the patient's own protection.  I would be more concerned with immediate dangers, such as fire, injury or wandering, when it comes to a dementia patient living alone, rather than their diet or preventative medications. 

Agree with the advice above, and....

You don't say how old your dad is, so I don't know if he's too young, but if he's not in a memory care facility, maybe he needs to be?

My mom has dementia, depression, and end stage renal disease. I've pretty much given up on trying to manage her diet - and I don't believe in force-feeding - but the meds are now managed by me and home support together. If it weren't for the fact that mom doesn't have much time left (because of the kidney failure), I have no doubt I'd have to put her in an MC facility. It only gets worse, and harder to manage. 

If he calls with an emergency, consider calling 911. Don't meet him at the ER. Let the staff step in and get him the care he needs.

Your profile says he lives at home. How is this possible if he has dementia? You just can expect him to take meds regularly or not have ER visits. Is there a reason he can’t be in a safer place like MC or AL so he can get supervision and medication management?
I agree with others that you can’t force him to do what he won’t.
This is hard for you I’m sure.

pambo, I’m sorry for all you have to deal with. I too feel surprised that he is living on his own, it sounds like a group living situation could be the best solution for him. Bless you.

Would like to butt in here and comment that a 'good, healthy diet rich in whole organic foods, fruits, vegetables, and whole grains' might result in a somewhat healthier looking dementia patient after some months. For what that's worth. It's still a downhill slide. My mother ate whatever she wanted per takeout - pizza, fried food, burgers, Chinese food. Otherwise, she had to make do with the dreaded processed foods, frozen dinners, sandwiches, and crackers and cheese. Why?  There was no one there to see to her diet 3 x a day 7 days a week. Between the shopping, the cooking, the cleaning, the doctors visits, the laundry - there was no time to cater to the ideal healthy diet we are all supposed to follow now. Just nuking a carton of mac and cheese was as good as it got at the worst times... Finally got her into a nursing home where she had what looked like a fine, well-balanced diet, certainly better than she was getting at home.

Who lives with Dad with his severe memory loss? If it is really that bad, then exercise your POA. If you let him flounder, then guilt feelings will haunt you especially if he comes to a horrible end. The choice is yours but not to protect someone who obviously doesn't want to help himself to me is wrong. Take charge and your conscious will be free.

Wow sorry to hear that. If he has a personality disorder, it may be difficult to discern that from dementia. Severe narcissistic personality disorder can appear to be dementia in obstinate older folk.

I agree with calling 911 and not meeting him at the hospital. Maybe they can get a home health aid from medicare to go to his home.

Here is an article regarding nutritional deficiencies and other medical conditions that can contribute to dementia or make it appear as if someone has Alzheimer's disease.

A B12 deficiency can sometimes be a culprit, it causes anemia, and it is an easy fix to give B12 by injection:

In older people, the first symptoms of pernicious anemia are often confusion, slowness, irritability, and apathy. Other symptoms of pernicious anemia include:

yellowish skin
fatigue
shortness of breath
headaches
numbness or tingling in the hands and feet
trouble keeping balance

Usually the B12 deficiency that underlies pernicious anemia is not caused by a lack of B12 in the diet. That’s because this vitamin is plentiful in eggs, dairy products, meat, fish, and poultry, and it’s efficiently stored in the liver.

Instead, a B12 deficiency usually occurs because an individual can’t absorb the vitamin from food. Fortunately, B12 injections, if started early, can remedy the deficiency and alleviate the symptoms of pernicious anemia.

helpguide.org/harvard/whats-causing-your-memory-loss.htm

I have found myself saying this a lot lately, do what your dad needs, not what he wants. That’s the best way of loving him. This comment relates to where he lives, he probably wants to live independently, but that’s not what he needs.

And to your question, let him be.

The key word here is narcissism. Once that word is part of a sentence one must know one cannot win. He will not change, specially now with dementia. So any effort of yours will be an uphill battle with no success in the horizon.

Love him, always care for him, place him where he is properly taken care of. That will solve most of the issues that are part of your question.

God bless you and your dad on this journey!