Mom is barely making it financially now but the POA (also executrix) says that doesn't concern her. What options do we have?

My mother has severe memory loss and doesn't care for herself or her four dogs. I am the eldest of six children and live closest to Mom. She often calls me two or three times a day to tell me about an incident that happened yesterday, which actually happened weeks ago and I've heard the story 40-50 times. Her house is impossibly filthy. She smokes 2+ packs a day and allows her dogs to relieve themselves on pads spread all over the house. Although difficult to breathe inside she won't allow opening a window as someone might hear the dogs bark and report her. My children clean and run her errands 6-10 times per month but it's a mere bandaid on a very bad situation. After my father died in 2009 Mom gave durable power of attorney to sister four, who is a classic enabler. When I bring the multiple problems up with the POA she says to leave her alone, she is merely allowing Mom to live independently as she wishes. I might also mention that our youngest brother cleaned out Mom's $27,000 savings account in six years, mostly with her permission, right under the POAs nose. Mom is barely making it financially now but the POA (also executrix) says that doesn't concern her. Upon Mom's death she plans to sell her assets and hope to recoup some of "her" expenses. Wth? It's my eight kids who are expending their resources to try to hold the sinking ship together. Do we have any options?