Astral Sight, is the phrase you are looking for. And trust me it can be rather bother some. The only thing I would suggest for your friend would be to learn how to control the on off functions of it. Realizing that the things that he sees are also not in the pysical will help also.
Ok guys, this guy I know is into magick and all kinds of stuff, and he told his little brother how to do this AP method where you think about what you want to dream about before you go to sleep. Anyways his little brother is in boy scouts with me(ya that's right boyscouts....) and we were on a camping trip and he was describing yhis to me. He also kept freaking out when we went into this big out-doors church that is just a roof and pillars. He said he could see excrement moving around on the ceiling in the corners and stuff, so either, he has like a permenant astral link, or he's schitzophrenic, or schitzophrenia is actually AP while still concious...hmmmm