Is it anorexia or not?

I am concerned about a female friend of mine who is 49. She has lost a lot of weight in the past 6 to 12 months. She look anorexic. I have confronted her a couple times She swears she is not anorexic. She been to several doctors now. She get light headed when she stands. Her blood pressure drop when she stands. She has fallen 3 or 4 times in the past month. Her last doctor said she has water on the heart, wherever that means. If she eats, the food just goes right thru her and then she is in the bathroom 2 to 3 times in the hour after she eats.

Is this a severe case of anorexia nervous or could it actually be something else?