Can I file elder abuse charges against my sister on behalf of my deceased mother?

our mother did not die as a result from my sister's care, but she was abused for 19 months. I witnessed and recorded such abuse while battling my sister in court over a guardianship to help provide proper care for my mother who was terminally ill. My sister did not want my mother to have a guardian and my mother was a victim who could not speak negatively about her abuser. My sister wanted to continue as her sole caregiver and now has taken my mother's home and finances. I presented the abuse, although the case was strictly about competence, and thought the judge would take proper action, yet Judge left her in my sisters care. Sadly, my mother died 2 weeks before her trial date.