He is afraid that he caused his wife’s death
Question

                My wife died recently (pregnancy complications) and during the 5-8 months pregnancy period, me and my wife quarreled on some issue and I did not telephone her for 3 months. When she was admitted to the hospital due to her serious condition, I came back from Saudi Arabia and I met my wife in the hospital and we forgot about our issue of quarrel. I kissed her and spent a lot of time in the hospital sitting with her and pursuaded her that, In sha Allah, she will be alright and I spent nearly 15,000 S.R towards medical expenses but she died. Q:1) Did she die because I was not talking to her on the telephone and she took this matter seriously in her heart ? Q:2) My mother-in-law blames me for the cause of her daughter's heart because I was not sending sufficient money for her because my mother wants my wife to stay in our home rather than staying with her parents. My mother told me that if I send money she will not come back to our house, so I used to send only a little money. Could that be the cause of my wife's dealth as my mother-in-law said ? Please help me and I feel very much guilty upon hearing my mother-in-law's words as I can not sleep properly and am feeling quilty. It was a love marriage and we quarreled on small issues sometimes, but I never wanted her death.
Praise be to Allah.
    Firstly: wWe ask Allah to shower your wife with His mercy and 
    to record for her the reward of martyrdom, because the Prophet  (peace 
    and blessings of Allah be upon him) said: “Martyrdom is of seven types 
    besides being killed (in jihad) for the sake of Allah,” ...and among them he 
    mentioned the woman who dies because of pregnancy or childbirth. Narrated by 
    Abu Dawood, 3111; al-Nasai, 1846; classed as saheeh by al-Albani. And we 
    ask Him to help you and her family to bear this loss with patience and to 
    compensate you in this world and in the Hereafter. 

    Secondly: There is no doubt that life and death are in the 
    hand of Allah and that the time of death and life-spans are decreed by His 
    will. Allah says (interpretation of the meaning): 

    “Who has created death and life that He may test you which 
    of you is best in deed”

    [al-Mulk 67:2] 

    “La ilaha illa Huwa (none has the right to be worshipped 
    but He). It is He Who gives life and causes death”

    [al-A’raf 7:158] 

    No one has the power to benefit or harm another except by 
    Allah’s leave. The Prophet  (peace and blessings of Allah be upon him) 
    said: “The Holy Spirit inspired to me that no soul will ever depart this 
    world until it has completed its allotted time and used up its allotted 
    provision, so do not be too desperate when seeking provision. If you feel 
    that provision is slow in coming, do not try to hasten it by disobeying 
    Allah, for that which is with Allah can only be attained by obeying Him.” 
    Narrated by al-Tabarani, 8/166; classed as hasan by al-Albani). 

    Thirdly: Islam enjoins kindness. The Prophet  (peace and 
    blessings of Allah be upon him) said: “Allah has prescribed kindness in 
    all one’s affairs.” Narrated by Muslim, 1955. The Prophet  (peace and 
    blessings of Allaah be upon him) even spoke of a woman who went to Hell 
    because of a cat that she detained until it died. Narrated by al-Bukhari, 
    2365; Muslim, 2242. 

    To what degree then do you think Islam enjoins kindness 
    towards one's wife– one’s companion in this world and in the Hereafter?  

    The Prophet  (peace and blessings of Allah be upon him) 
    said: “I urge you to treat women kindly.” Narrated by al-Bukhari, 3331; 
    Muslim, 1468. 

    Al-Imam al-Tirmidhi narrated a hadeeth (1163) which he classed 
    as hasan, and al-Albani agreed with him, according to which the Prophet 
     (peace and blessings of Allah be upon him) said, during the Farewell 
    Pilgrimage: “They (women) are like prisoners in your hands.” 

    It was narrated from Abu Hurayrah (may Allah be pleased with 
    him) that the Prophet  (peace and blessings of Allah be upon him) said: 
    “The most complete in faith of the believers are those who have the best 
    attitude, and the best of you are those who are best towards their 
    womenfolk.” Narrated by al-Tirmidhi, 1162; classed as hasan by al-Albani. 

    Fourthly: If you know from the above that you fell short in 
    your duty towards your wife, by cutting off communication with her when she 
    was sick and was most in need of you, and the quarrel between you was about 
    some minor issue, as you mention, then how could you fall short in spending 
    on her, for spending on one’s wife is obligatory according to the Quran 
    and Sunnah, and scholarly consensus, as it says in al-Mughni (9/229)? 
    If your mother told you to do something other than that, you should not have 
    obeyed her, because there is no obedience to any created being if it 
    involves disobedience towards the Creator. Your feelings of shortcoming and 
    sin are appropriate. The Prophet  (peace and blessings of Allah be upon 
    him) said: “Righteousness is a good attitude, and wrongdoing is that which 
    wavers in your heart and which you dislike people finding out about.” 
    Narrated by Muslim, 2553. 

    But this sin should not be regarded as the cause of your 
    wife’s death, because it is not directly connected to it and such things do 
    not usually kill a person. You mentioned in your question that she died 
    because of complications in pregnancy. And you did well – may Allah reward 
    you with good – by sitting with her in her last days and spending on her. 
    Your doing these things will be an expiation for you in sha Allah. 

    Our advice to you is to pray a great deal for forgiveness for yourself and for her, and make du’a for her, give in charity on her behalf, honour her family and uphold your ties with them and treat them kindly; put up with any bad treatment you may encounter from them because of the loss of their daughter; and let what happened be a lesson for the future so that it does not happen again. 

    And Allah knows best.