What are the best ways to solve the problem of a sister discovering pornographic images and videos on her 17-year-old brother's computer?

It is not permissible for a Muslim to look at pornographic pictures and films. A Muslim woman must advise her brother who possesses such files to give them up, reminding him of Allah's watchfulness and His punishment, and that death comes suddenly, and the servant will be questioned on the Day of Judgment about his deeds. She can offer him Islamic reminder materials and move the computer to a common area in the house to prevent him from being alone. If he insists on his actions, the matter should be brought to the parents and not covered up. She must not look at those pictures under the pretext of checking or spying on him, as checking them is forbidden, and spying is prohibited by religious law.