Sorry, do not mean to disillusion (sp?) you, but yes prolonged use of pot can ruin your lungs, as well as smoking cigarettes, but pot has more resins and are retained in the lung tissue, so if she has used it often, she can be suffering from the effects it has on your lungs, 2 things for her, is to STOP the pot and then see her doctor to rule out other things like TB, etc. but I am sure it is the use of pot that is causing this, even it's affect on her GI tract.
Just my 2 cents, from a 47 y.o. woman who has been there and done that

Take care,
DE

In giving advice seek to help, not please your friend
SOLON