Mom makes weird motions with her mouth and tongue.

Is her mouth being kept moist enough? You might want to get some of those lollipop-type mouth moisteners so she’ll be more comfortable.

Try researching Tardive Dyskinesia

Look up "involuntary mouth movements in dementia, and you will find the internet full of information on this. It is extremely common.

There is also tardive dyskinesia which can come as side effect from some medications.

Remember the internet is your friend in that you can type in almost anything you find troubling you and come up with a host of information there.

I wish you the best in tracking down exact cause and possible treatment. Remember to discuss with MD at next visit.

Speak to her doctor about it if you are concerned.