My feeling is that if the two of you are truly good friends, she ought to be able to handle you bringing up the problem and, if she can't handle it or blows you off, then perhaps that tells you something re the strength of the alleged friendship. Her squeamishness re bodily functions and your disgust about it cause me to wonder about the prospect for sustaining the relationship, frankly. However you decide to deal with the situation, I can mention what I do to minimize odor. Being a cheapskate, I disdain expensive odor prevention products and use plain ol' baking soda (the yellow box that people put in their friges to absorb odor). I just shove a little bit in after emptying the pouch. As far as I can tell, I don't have an odor problem.
I had a cousin who had surgery to loose weight. Can't remeber what it was called but I think they stapled part of the stomach . Everytime he ate it straight throw him and he could not hold it back. It was the worst smell I have every smelt and it would go through the whole house before he even came out of the bathroom. Someone would say you can tell when (so and so) is in the house and everyone would laugh including him. As you said HenryM she should not be offended, I am sure she knows it stinks just like my cousin did. Or maybe as a commercial I saw said she has become nose blind. When my cousin came to my house I would spray after him, it helped some. Maybe her output is high and she has to empty often and not just when her friend comes over. Ok I will stop now.