What is the ruling on a person benefiting from money won in a competition, if the winning montage was prepared using a cracked program by another person, and does sin befall the maker of the montage, knowing that communication with him has been cut off?

As long as communication with your friend has been cut off, turn your mind away from thinking about the matter, seek Allah's forgiveness for what has passed, and attend to your religious and worldly affairs. Do not deny your friend the prize if he wins it, even if he used pirated software, but the user of pirated software guarantees what he has caused his companions to miss out on in terms of benefits. If the competition organizers stipulate that the contestant must do the editing himself, then deceiving them in this regard is cheating and deception, which is impermissible to do or to assist in. If you have assisted him, then seek Allah's forgiveness, but it seems that these are merely doubts and delusions, and communication with the man has been cut off, so stop thinking about that.