Maybe I would, but I'd honestly refrain. When friends suddenly pop up to defend a person, it usually makes things worse. There's now two sides that are going to go back and forth: one that asserts she's not right and one that's just defending a friend. All it would cause is more fighting.

Again, your friend has to handle this by herself. She's an adult and she can take care of herself. If you want to sympathize and comfort her, that's fine, but don't fight her battles or you'll get sucked into something manic.