Marriage, Green Card, etc.

[Washington]

My question is complicated. I have a friend who is a Kenyan citizen. She is here in the U.S. on what I believe is an H1B Visa. Her company was able to fanegel her paperwork stating that she works for a non-profit. However, the organization that she works for is not entirely non-profit.
She started out on a student visa, graduated and now works full time here in the U.S.
She is dating an illegal Brazilian alien. He does not have citizenship in the U.S., but orignally came here on a work visa and let it expire. My Kenyan friend is now applying to get a green card. What does a green card entitle her to? How long will it take her to get it? Her brother, who was just naturalized as a citizen last August (2008) is going to sponsor her. Also, if my Kenyan friend marries her Brazilian boyfriend will their marriage be recogized by U.S. Law as a legitimate legal marriage? If she is able to obtain a green card, before they get married, will her Brazilian boyfriend also be able to apply for a green card or citizenship?
Both my friend and her boyfriend live in Boston, Massachusetts.