His grandmother is sick and is unconscious; does she have to offer expiation for not fasting?
Question

                My grandmother has been sick for nearly a year and a half; she is not aware of her surroundings and does not speak and does not ask for food, but when we give her food, she eats. Sometimes she knows who is speaking to her (which is rare), but she does not tell us what she wants from us (she does not say: “I want a bath, may Allaah bless you”). She is sleeping on a bed without moving, and her children help her to move. I want to ask about fasting and prayer; should we pay fidyah on her behalf and do we have to do anything for the time that is past?.
Praise be to Allah.If a person reaches a stage 
    of senility and feeble-mindedness, loses his or her mental capacity and is 
    no longer aware, the obligations of fasting and prayer are waived, and he 
    does not have to offer expiation, because one of the conditions of being 
    accountable is that one should be of sound mind.  
The Prophet (peace and 
    blessings of Allaah be upon him) said: “The Pen has been lifted from three: 
    from the sleeping person until he wakes up, from the minor until he grows 
    up, and from the insane person until he comes to his senses.” Narrated by 
    Abu Dawood (4403), al-Tirmidhi (1423), al-Nasaa’i (3432), Ibn Majaah (2041). 
    Abu Dawood said: It was narrated by Ibn Jurayj from al-Qaasim ibn Yazeed 
    from ‘Ali (may Allaah be pleased with him) from the Prophet SAWS (peace and 
    blessings of Allaah be upon him). He added “and the senile”.  
This hadeeth was classed as 
    saheeh by al-Albaani in Saheeh Abi Dawood. 
It says in ‘Awn 
    al-Ma’bood: Senility refers to when the mind becomes no longer sound 
    because of old age. What is meant here is the old man has lost his mind 
    because of old age. The elderly person may become confused and lose his 
    power of discernment, which means that he is no longer qualified to be 
    regarded as accountable, but he cannot be called insane. End quote. 
Shaykh Ibn ‘Uthaymeen (may 
    Allaah have mercy on him) said: Fasting is not obligatory unless certain 
    conditions are met: (i) being of sound mind; (ii) being an adult; (iii) 
    being a Muslim; (iv) being able to do it; (v) being resident (i.e., not 
    travelling); (vi) being free of menses or nifaas (post-partum bleeding), in 
    the case of women. 
With regard to the first, 
    being of sound mind – the opposite is loss of reason, whether it is due to 
    insanity or senility, meaning old age, or an accident which causes a person 
    to lose consciousness and feeling. Such a person does not have to do 
    anything, because he is no longer of sound mind. Based on this, this elderly 
    person who has reached the stage of senility does not have to fast or feed 
    the poor, because he is not of sound mind. End quote from Liqa’ al-Baab 
    al-Maftooh (4/220). 
With regard to the past, if 
    she was in this state, and was not aware and could not understand anything, 
    then she does not have to fast or offer expiation. 
If she was aware and could 
    understand, but she did not fast because she was sick, then one of two 
    scenarios must apply: 

    1.If at that time she was hoping 
    to recover from her sickness, but the sickness continued, then she does not 
    have to do anything, because what she had to do was make up the fasts when 
    she recovered, but she did not recover.

    2.If at that time there was no 
    hope of recovery, then she should offer expiation for each day, which is 
    feeding one poor person, half a saa’ of the local staple food. If she did 
    not offer this expiation, then you must offer it now from her wealth.
We ask Allaah to heal her and make her well, and to guide and help you. 
And Allaah knows best.