Hi Grumpy Twin and welcome,
First, let me say I am NOT a healthcare professional, but I do have a mom with Alzheimer's. Not sure what stage she is in, going on her tenth year since diagnosis, probably at end of midstage or beginning of end stage.
In the early years after her diagnosis, I spent hours, days, weeks, months reading about dementia and Alzheimer's. From what I remember, in end stage, the Alzheimer patient stops eating. I also remember something about Alzheimer's causing the inability to swallow. Could this be why she is holding her throat? You might want to try chopping her food into small bits, or mashing things like mashed potatoes. Are you caring for mom at home? If so, have you contacted the Alzheimer's Association? They do have a support hot line and are very informative.
I wish you well,