My friend was given voluntary departure but her husband is a legal US resident. Should he include her in his taxes and file as married or what?

I think he can include her if she lived with him for at least 6 months out of the year and not filing herself. Then again her not being legal citizen he might no be able to.

A legal U.S. resident can file jointly with his/her spouse regardless of the physical location of the spouse. The spouse can be in Africa, Europe, India, China, or anywhere else in the world.

The only catch is that, if the spouse files jointly, the spouse must declare and pay tax on ALL WORLD-WIDE INCOME.