Lifting of Obligations from One Who Has Lost His Mind

The honorable Shaykh! A man instructed me to ask a question, and its text is: Her mother is (85) years old, and she has been struck with paralysis, and her tongue has become inarticulate. She does not pray and does not fast. What is the ruling on this? And what should be done for her? She has been in this condition for approximately six years!
If the mother has lost her mind, such that she does not take anything and does not give anything, then she owes no fasting and no prayer, and no charity is given on her behalf; because the obligation has been lifted from her due to the loss of her mind.