Will a person be sinful for committing a sin without his mother's knowledge, for fear of angering her, with the possibility of committing filial disobedience, and is using her device to study religion without her permission considered filial disobedience?

Angering parents is one of the gravest major sins, and this is particularly emphasized concerning the mother. The matter becomes even more sinful if the mother's anger is due to an act of disobedience, as the son then combines the sin of disobeying Allah with the sin of angering his mother. It is not permissible to use the mother's device without her knowledge if she prohibits it, as this constitutes an unlawful transgression according to Sharia, and using it for seeking religious knowledge does not justify it.