it might not even be that she is an awful mom that abandoned her passion to care for her cfer, or that she cares more for the new additions. i am a very committed cf parent, but at times I get fed up and angry with my daughter, the love of my life, when she fights me about her cf routine, when I am trying my hardest and she lies to me about checking sugar, taking insulin, doing nebs. i then get very discouraged and feel shes too blame for exaserbations and hospitalizations. Im wrong for that, I know, but what she knows it takes away from my other kids when she is sick, and to ignore her daily health anyway?
Not defending your sister. but 17 is a trifling age, there may be more to the negativity. Just a thought.