Illegal alien marrying a green card holder - procedure!!!?

Hi, I have a friend who is a green card holder and is eligible for naturalization in less than two years (she has been in the US for a little more than 3 years). She is marrying a person who overstayed his status and is considered an illegal alien. Can she still apply for naturalization in two years? And can her husband benefit from the two years they would have been married by the time she applies for her citizenship if/when they apply for adjustment of his status to permanent residency? In other words, will the INS consider the time spent together as a married couple in favor of her husband's legalization proceedings? Your answers and comments are greatly appreciated.