Mom supports sister, her boyfriend and her two kids, one is the boyfriend's. No one works.

I don’t want this to be long I’m looking for different perspectives. My sister lives with my mom and is supposed to be her “caregiver” my mom used to text me because she is so lonely. I work graveyard shift and am also experiencing a cancer reoccurrence and am exhausted all the time. Prior to this I would take my mom to all her appointments because it was “inconvenient”

for my sister. Even though she doesn’t go anywhere. Work or otherwise. Her kids do school online. So when I became ill again I expected my sister to handle my moms many appointments. She is in severe pain all the time. So I get the appt reminders also and I’ve discovered she is not being taken. I had to go to their house because my sister called and said she thought mom was having a stroke. I told her call 911. I’ll come over right now. I had just gotten home from a brain MRI after also working all night. So I was exhausted. I got there. EMT arrived. They took my mom to hospital. My sister said she couldn’t go and asked me to. I went. As I sat with my mom we began having conversations about finances and how I was concerned about how she was feeling. She said she was sad and hurt that she was being yelled at for going into the fridge. My mom cannot walk. So she often soils herself. Etc. she can’t walk and is told she is disgusting etc. just really very mean and what I feel is abusive behavior towards my mom from my sister her boyfriend and her two kids. My sister is 39 she plays video games all day. Her boyfriend works “under the table” very infrequently. He spends his money on pot. And my sisters two kids 16 and 11. The older child is mildly autistic and does online school because my sister is super paranoid about the whole covid thing. Every thing is an excuse with her. So my mom pays for everything. My grandmother recently passed and left an inheritance that was broken down. However my sister is receiving everything claiming she takes care of mom. So she uses my saving accounts for certain shopping outlets. So I have receipts in the digital cloud for everything. She spends upwards of $600 dollars every 5-6 days on groceries. She goes to amusement parks. Hotels etc. spends all kinds of money on electronic devices for everyone. I told my mom. When you run out of money what is going to happen. Prior to her receiving the inheritance my brother and I were buying groceries. I was already strapped due to my many medical bills but I felt bad for the kids and couldn’t let them starve. But then my sister just didn’t do anything to help any situation. The boyfriend refuses to get a paycheck job because he owes child support back pay. That’s a red flag. So my question is this. Do I just wash my hands of this. Or do I step in and take POA and place my moms money in a trust and hire an actual caregiver that isn’t going to hurt my mom emotionally. My sister won’t even do my moms laundry. My mom has enabled this situation by not demanding they pay their way. Even before my became disabled my sister and boyfriend freeloaded. My sister plays victim constantly. Now I don’t even get calls on holidays. She passive aggressively invited me to dinners with other sibling dinners then immediately told oh Nevermind no room. It’s disgusting. I feel like she doesn’t want anyone interfering with her agenda. Help me understand what steps I should take. Do I call APS on my sibling?