Welcome to HCM
I understand your concern
Please don't conclude anything.
Your mother is 81 and she is suffering from old age anxiety
What she really need is affection and love from your side.
At least don't don't misunderstand her.
And don't hate her for this, because at our old age we are also bound to do the same.
The most you can do is to take her to a psychiatrist
But I don't advice it.
Keep your mother happy, because once she did everything to keep you happy.
Wish her and you a happy life.