All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First of all we ask Allaah to magnify your reward and make better your solace and forgive your mother, sister and relative. We advise you to take it easy and know that this worldly life is not an eternal life but it is a test for us. Among the things that would help you to be patient about this calamity that has befallen you is to remember that it was predestined by Allaah. A believer should believe in the Predestination of Allaah; this would help him to be patient and be pleased about the Decree of Allaah. The Prophet said: "The greatness of the reward stems from the greatness of the affliction. When Allaah loves a people, He tries them. So, whoever is content (with such distress and calamities), will get the reward of being content, and whoever is angry and displeased, will get the punishment of being discontent." [At-Tirmithi] Therefore, you should not be displeased about what Allaah has predestined. You have to know also that when a person has a strong belief, Allaah may afflict him with more trials and calamities, so that He would increase his degree in
The Prophet said: "A man is afflicted according to the degree of his religion, if he is very well grounded in religion and patient, then he is afflicted with more calamities." [At-Tirmithi]
We advise you to supplicate Allaah as much as possible to forgive them and avoid pondering about what has already taken place. Moreover, it is not permissible to express yourself in the way that is mentioned in the question which suggests that you are angry and not pleased with what had happened.
Finally, we advise you to the following matters:
Firstly, it is not required that a supplication be granted in a way that is clear to us; it could be that the same supplication is answered, or that Allaah saves the person from an equivalent evil, or that the reward will be reserved for him in the Hereafter.
Secondly, the martyrs in the Hereafter are so many, among whom are those who died in a collapsed building, or drowned, or burnt, and the like, as confirmed in the Sunnah.
Thirdly, and the most important, be careful regarding doubts about the faith, as this is Kufr (an act of disbelief); we seek refuge in Allaah from that. The Prophets, may Allaah exalt their mention, were the most devoted and pious people, yet they were the most afflicted among the people. Some of them were even killed, but this did not cause them to doubt Allaah.
Allaah knows best.