Tell your friend that he's completely stupid. Rush is one of the most influential bands ever. They influenced pretty much every progressive rock and metal band that came after them. The individual members of Rush even influenced the playing of people of the same instrument who aren't even in progressive bands. From a drummers perspective I can tell you that 99% of rock and metal drummers worship Neil Peart as one of the drum gods. Check out their documentary "Beyond the Lighted Stage", there is a section that has guys like Kirk Hammet, Sebastian Bach, Billy Corgan, Les Claypool, Mike Portnoy, Vinnie Paul, Taylor Hawkins and a bunch of other guys from famous rock and metal bands all talk about how they were influenced by Rush in some way.