There's your answer, then - continuing to use laxatives is just exacerbating the problem, because they interfere with your body's fluid regulation. Laxatives flush out the large intestine, where water - among other nutrients - is absorbed.
At any rate, unless she wants to take those things for life, your friend should probably taper down her laxative use as soon as possible, while eating lots of fiber to keep things "moving" in there. And although I don't advocate getting all of one's nutrition from meal replacement bars, most people find that eating several protein bars a day has a laxative effect, so she may find it easier to go to the bathroom if she keeps eating them. In time, however, incorporating real food into her diet should be part of the recovery process. Best of luck to her.