Teaching a child to use Google will show you that there is indeed quite a learning curve. It is not intuitive how you evaluate your results and refine your search to get good results.
I hated to have to disappoint him.
e.g. "x y z" ~ "x y z" + "x y" + "y z" + "x z" + "x" + "y" + "z"
where "+x y +z" ~ "x y z" + "x z"
Still, I would imagine this isn't exactly the behavior your friend would have expected.
https://productforums.google.com/forum/#!topicsearchin/webse...