Is the grandmother who died of cancer, and who did not pray well despite attempts to teach her, considered a martyr, or is she in hell because of her failure to perfect her prayers, especially since she screamed before her death?

We hope that Allah will have mercy on your grandmother and forgive her. She is excused due to her ignorance or inability to learn, for the Messenger of Allah, peace and blessings be upon him, did not command those ignorant of the rulings of worship to repeat them if their time had passed. Her fate is a matter of the unseen, but Allah's mercy is vast; He is more merciful to His servants than a mother to her child. Allah Almighty said: "And My mercy encompasses all things." And since she died from an abdominal illness, she is considered among those who died of an internal ailment, and martyrdom is hoped for her.