You can have informal advisors who aren't investors. But it's usually a bad idea to have a board of advisors, for example, or to give stock to people who want it in return for being an advisor, yet for some reason don't want to actually invest in you.
The one exception is when you're a grad student and start a startup based on your research. Then it's common to give your (faculty) advisor some stock.
The one exception is when you're a grad student and start a startup based on your research. Then it's common to give your (faculty) advisor some stock.