What is the optimal way to deal with a 17-year-old brother who does not pray and is addicted to computer games, knowing that he previously watched pornographic websites, and his father resorted to beating him to make him pray and abandon these practices?

Your brother is an adult and accountable, and he needs care and attention in these times of tribulation. Therefore, he should be followed up with, advised, and guided to what benefits him in this world and the Hereafter, and warned against wasting time. Let the advice sometimes be with gentleness and leniency, sometimes with strictness, and sometimes by withholding the computer or financial assistance. The computer should not be completely taken away from him to avoid a negative reaction; instead, a specific time should be set for him, and he should be asked about what he has read, done, and the websites he browses. Guidance is in the hands of Allah, and all you have to do is exert effort and supplicate for his guidance and bring good company to him.