Hi everyone, well my band mate which is the rhythm guitarist on my band. He doesn't play very well seriously, but well i want to help him to play guitar nice. So if there any songs that can recommend to him? He like a lot thrash metal so this can give an idea of which songs to choose. Also is thre any good exercise that can help to him with the rhythm guitar?

Thanks In Advance
(i hope I've put my thread in the right section).
Sorry for my bad english