Can the son's anger and shouting at his deceased mother be the cause of her death, and what are the consequences if that is the case, and how can he rid himself of the feeling of shortcoming towards her?

Filial piety is among the most obligatory duties, and disobedience to parents is among the greatest sins. Shouting at one's mother and reprimanding her angrily is a grave error. Piety towards one's mother after her death is achieved through supplication and charity on her behalf, and by maintaining ties of kinship through her. The verse: "Your Lord is most knowing of what is within yourselves. If you should be righteous, then indeed He is ever Forgiving to the oft-returning [to Him]" indicates that Allah forgives unintentional slips towards parents if the children are righteous and intend to be dutiful to them.