I came back to make a brief report on mom - both as follow up for people who read this thread later and as a kind of record of where things stand for mom at this point.

It's been about three weeks. Mom is getting a high-fat, low-carb diet with maybe a bit too much protein to be highly ketogenic. I'm adding MCT oil to her protein drinks - a tablespoon per drink, so 3 to 5 T per day. It doesn't seem to have upset her stomach.

Her mental condition is not improved. If anything, she's worse. She formerly had at least an interest in what was on tv. Now she shows little interest in anything. She sleeps a lot.

There's a confounding factor. Her doctor had prescribed an antidepressant called mirtazapine to increase her appetite. I didn't give it to her, because she had another appetite-stimulant called megestrol which was working. Unfortunately her insurance won't pay for it, so I may have to discontinue it when her current supply runs out. So about six days ago I started the mirtazapine and gave it to her for three days. It was dreadful. She became even more confused and listless, and she slept nearly the whole day and night. She started saying she couldn't stand up to go to the bathroom. I discontinued the medication, and she's now a bit more alert.

I tried to research how long I should continue this experiment before I decide it's not going to be helpful for my mother. Since this isn't really a treatment that's widely used for dementia, I checked the experience for epilepsy. Evidently it can take up to three months to tell if it's going to help. I did find a case study with a patient with advanced Alzheimer's which noted he showed improvement after two and a half months.

So, I'll continue for two or three more months before abandoning the effort.