being a sibling and having that conversation with her under your belt, i assume these family members are nothing more than hassle during this traumatic time, i doubt they have any sort of case.
at this time in my life i've no commitments or posessions that would matter a great deal were i not here, so i've no need for a will at the moment, rest assured the moment that changes then i'll write a will and put it in my "special things" box.