The progression of heart failure can be unpredictable, which makes it difficult to know when to have conversations about end-of-life care. I would advise discussing things as early as possible, giving your friend time to think about treatment options and where she wants to be cared for towards the end of her life. For additional guidance on planning for advanced heart failure, please refer to relevant section on American Heart Association web site: https://www.heart.org/en/health-topics/heart-failure/living-with-heart-failure-and-managing-advanced-hf/planning-ahead-advanced-heart-failure
Progression of CHF could be painful, or not. Usually CHF is not painful, but the anxiety could make the heart beat faster, which means that it could cause pain since the enlarged heart tries to beat faster, but it can't due to it being enlarged. To fix CHF, she needs a heart transplantation ASAP! Since the demand for donor hearts are limited, you can be forced to be on a list that could either help you get a heart within a week, or to where you have to wait for a few years to get a heart. Is she on the list? If so then tell her to stay strong, if not, then I'm sorry that she is going through this. The quick fix to this situation is a heart transplant, and then to make her "new" heart pump less hard, they'll have to remove the swelling from her feet. My mom had end stage heart disease that was caused by cancer. She died before I was 13... yea, it was sad, but anyways, if you can, tell her to try to get a heart transplant. If not then keep an eye on her and keep prescribing her medications. Usually throwing up with medications are caused by her not eating food, then taking the medication. Anyways, your friend are in my prayers homie!