What should a fourteen-year-old girl do when her paternal grandfather interferes with her modest clothing and hijab, and sabotages her father's work, while her father remains silent to appease him, and her mother lives like a servant in the house?

You must be dutiful and kind to your grandfather, for this is an Islamic obligation and will be rewarded by Allah. You should be happy that your parents possess praiseworthy qualities, such as your father's dutifulness to his own father, and your mother's patience with household burdens. These factors contribute to a happy home, and patience and endurance have good consequences in this world and the Hereafter. As for your grandfather's strictness regarding the hijab (definition), it stems from his concern for your honor and your religion.