Best video editing tool for teenager ?

[cbelt3]

My youngest is getting into making videos for his school and friends. He's using my Mini (16G RAM, dual core 2.6GHz A5, Yosemite ). What would be a good tool (with edu discount, natch) to get him to use ? I stopped at iMovie, so have no clew....

I expect he would migrate to more industrial strength if this went serious...

tia !