Prohibition of Lying
Question

                My mother is still alive and is over one hundred years old. She is in a difficult situation because she cannot understand things, and she asks whether it is evening when it is morning, and she repeats words more than five times. She cannot move from where she is, and if she has been sleeping she is not able to sit up, etc. Her children answer all her questions, but their answers may be lies, such as when she asks them in the evening whether it is the morning, and they tell her yes, even though it is the evening, and so on. My question is: if they tell her lies, are they sinning or not? The second question is: is there any kafarah (expiation) which they should pay to make up for her fasts and prayers, or not? Please advise us, may Allah reward you with good.
Praise be to Allah.
    You 
    should not tell her lies; you should tell her the truth, because telling her 
    lies does not serve any purpose or benefit her in any way, or make her 
    happy.

     With 
    regard to prayer and fasting, there is no kafarah to be paid, and there is 
    no sin on her, because she has become like a child. So long as she cannot 
    tell what is what, and her feelings and mind have changed, she is not 
    obliged to pray or fast, because she is not held accountable for that. She 
    is now like a little child who is free of responsibility and there is no sin 
    involved, in sha Allah. 

    And 
    Allah knows best.