L.
I think that this is tough. I think the Mom should first try to sit down with the daycare and try to work out a solution first.
Also, the Mom should work with him at home to understand that while that is fun, some people might not understand. Try to channel it into other imaginative play. Or say that instead of sayign I'm going to fight you with my sword, maybe that he and the friend try to fight a pretend dragon.
I would also advise the Mom to switch to more age appropriate movie watching. Spider Man and Star Wars are not for a 3 year old, they are much too violet and scary for a child that age. Try Cars, or any of the Disney movies - they do have ones that are more boy oriented. There are also kid shows he might like - Thomas The Tank Engine (it has lots of crashes and my 3 year old likes it), Bob the Builder, Go Diego Go, Cailou, etc.