What should a mother do who lost her eight-year-old son in an accident and blames herself for depriving him of certain things?

It is recommended to show patience, gratitude, and to say "Innā lillāhi wa innā ilayhi rājiʿūn" (To Allah we belong and to Him is our return) when afflicted by a calamity. For Allah has prepared a great reward for the patient, as stated in His Almighty words: "And give good tidings to the patient, Who, when disaster strikes them, say, 'Indeed we belong to Allah, and indeed to Him we will return.' Those are the ones upon whom are blessings from their Lord and mercy. And it is those who are the [rightly] guided." The Prophet, peace be upon him, also clarified that whoever praises Allah and says "Innā lillāhi wa innā ilayhi rājiʿūn" upon the loss of their child, Allah will build for them a house in Paradise called "Bayt al-Ḥamd" (The House of Praise). Furthermore, young deceased children will intercede for their parents on the Day of Resurrection, awaiting them at the gates of Paradise and admitting them into it. Thus, there is no blame in preventing a child from what would harm them.