My friend is a owner of a band and the other band members had been remove from the band except the rightful owner

My friend is a owner of a band and the band members had been remove from the band except the rightful owner of the band which is my friend..he has been in that band ever since he created it.. the band still do exist because he is currently looking for new members. The issue is, that band created a video clip for their band and those other band member was in it.. they used that video clip to enter a competition without my friend consent and the copyright owner of that video because he paid for it.. they were qualified to enter the competition because of the video. but then they also use the band name without the owner permission. then they won the competition.. what can we do from the law point... my friend has not register the name of the band for trademark but he is going to do so a.s.a.p... and can we ask the organizer of the competition to revoke their price... if they do not revoke can we take action against them too??