Lazigirl
You raise a valid point. I also realize that I often come across as being more pragmatic than supportive.
From my perspective, I see someone going through a lot of angst and pain over matters that she never could control anyway. Whatever her perceptions and however complex or simple these issues are, 'stirring' the proverbial pot by means of a confrontation, will likely make things worse, not better.
Based on calculated risk these are the two choices...
To reclaim 'fair' share of the inheritance, asking nicely is not going to cut it (based on her post), so she will likely have to fight for it and even retain a solicitor Outcome? Alienate her sister even more (and possibly other family members) in the process....and if her legal claims go sideways, she'll have a lot of expenses and still not get what she wants!
On the other hand, if she's looking to warm up her relationship with her sister, she needs to forgive and forget. Outcome? Family ties remain/improve and a chance that she'll get some or all of what she wants.