I have a moral dilemma and could use some perspective from others.

My sister has a traumatic brain injury. She is not able to communicate at this time. A guardian is needed to manage medical care, wellness, insurance, finances, etc. My mother wants me to be my sister's guardian because I have been a guardian in the past (my father and maternal grandmother, both prearranged prior to the time when guardianship was needed)).

The dilemma is that my sister and I have never been close and generally speaking, dont really like each other. We are cordial, but I haven't spoken to her since Christmas 2019. I know that if she could communicate, I would be the LAST person she would want involved in her business. Unfortunately, due to some recent events, my brother in law is not able to be her guardian and my mother lacks certain traits needed to be a guardian.

I'm torn about this. On the one hand, a guardian is supposed to make decisions in the best interest of the incapacitated person, with a high regard for their personal wishes (my sister would not want me involved). On the other, I have both the experience navigating insurance, forms, required court submissions, etc and the integrity to put her best interests first in decision making. My sister didn't put anything in writing about her wishes,which makes it more difficult.

If anyone has any thoughts about either side of this, I would appreciate the input. My sister needs someone to be her guardian, I'm just not convinced I'm the person she would have chosen. I think she would prefer anyone else, even if it was my mother or a court appointed attorney.

I'm asking in the relationship and communication area because I'm not sure where else to post this. If it needs to be moved, please make the move to the more appropriate area.