add light sabers with a still shot green screen background, or show x-wing fighters in space?

For the first, anything will do, so I am assuming that's not it.

For the second, I agree with what the others have said - Adobe or daVinci.

For the third, though, he would need a 3d animation program, and if people in motion are to be included, probably one with a motion tracker. Blender 3d is free, powerful, all in one, and slightly less confusing than it used to be, but the learning curve is steep. Autodesk also has some expensive stuff (Maya and 3d Studio Max) but there might be student versions available.