On my visit to Mom, I noticed a new behavior. She pockets her food, forgetting to swallow.

I urge you NOT to consider a surgical feeding tube. Stick to the suggestions of pureed and thickened liquids. Forgetting to swallow is part of the end game of Alzheimers which is eventually terminal. A hospice evaluation will give you more information about her decline and guidance for keeping her as comfortable as possible. Could it also be possible that she is deciding not to eat? If this seems to be a choice, I would let her decide she is ready.

In the late stages of dementia this difficulty with swallowing is common, and often indicates end stages.
At some point it becomes problematic and there can be aspiration, and pneumonia. This is a discussion now to have with the medical team.

Sounds like it's time to have all moms foods pureed, and her drinks thickened to prevent best you can aspiration pneumonia.

It is time to ask the doctor for a speach and swallow evaluation. Not making changes to accomodate swallow defect will lead to chronic aspiration. And as other suggest, ask for a hospice consult.

If mom isn't already under hospice care, now is the time to ask her doctor to order an evaluation. Pocketing food can lead to aspiration pneumonia and sometimes death.

I'm sorry you're witnessing a new level of decline with mom, it's such a difficult and stressful thing to witness, I know. Sending you a hug and a prayer for strength.

I'm sorry you are seeing a decline in your Mom's behavior.
If she is having difficulty swallowing, or simply forgot how, a speech therapist can provide guidance for giving her nutrition safely.

You could try thickened protein shakes, with a straw, if she is able to manage that. If she doesn't recognize how to drink with a straw, you could show her by having your own drink, and let her mimic your actions.

She may need to be taken off food or drinks entirely. She could be fed through a G-tube, or intravenously. As people get closer to death, they will stop needing food or liquid as their body begins to shut down.