What should I do for Allah to forgive me for guiding one of my relatives to two movie websites, and will I bear his sins when he hears anything on them?

It is forbidden for a Muslim to guide others to sins, for Allah the Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression." And whoever calls to misguidance will bear a burden of sin equivalent to that of those who follow him. Sincere repentance from the sin is obligatory, as well as enjoining the one who was guided to it to refrain from forbidden looking and listening. If you do that, then the commission of the sin by the one you guided will not harm you.