My Mom is in nursing home, stepfather causing problems with myself and my sister. Any advice?

My mother was verbally & physically abusive to us kids when growing up. She is also very controlling and demanding to us as kids & adults and when she wants something, you better do it NOW! She went to the nursing home Dec 2014 on her own free will due to a light stroke and other health issues. My stepdad has been good to deal with the past 10 yrs they have been married. My real dad died in 2000, so mom remarried in 2004. Mom named me her Power of Attorney to handle her affairs, since her current husband (my stepdad) is 84 yrs old. Mom is 80 yrs old and does NOT have dementia. They have a pre-nupital agreement since he owns a farm/house so it goes to his adult kids upon his death. Mom has a very small piece of property in another state, that my sister and I will inherit. My stepdad's kids (his first wife died in 1998) are not the easiest people to get along with, so we keep our distance. His kids do not like my mom, because of her controlling and not very nice attitude toward them. I certainly don't blame them for feeling that way, they have the "evil stepmother". Therefore when my stepdad passes away at some point we do not want a confrontation with his kids when it is time to remove our mothers things from stepdad's house. My sister was here (she lives 850 miles away) we visited mom in the nursing home and then went to stepdads house to get a few family heirlooms-mom said my sister and I could have a set of dishes, among other things. We wanted to get those items out of the house now, to preserve those memories that mean something to us (family photos, etc.) before stepdad passes away-to avoid being accused by his kids that we are removing things from "their dads house.". There is no monetary value, only sentimental value. My stepdad called me and said he went to the nursing home and told my mom that we took "everything" she owns. Of course with her contolling personality she blew up and "demanded" that I go to the nursing home NOW because she wanted to speak to me. Stepdad also told me that we "stole from our mother" by taking those things. He was sitting at the kitchen table watching us pack these items up, so we did not "steal" anything. Had he kept his mouth shut and not told her his exaggerated story that we took "everything" this would not have caused problems, he knew she would throw a fit. He said it is our fault now because mom is depressed and upset. If he had not said anything to her other than yes the kids got your dishes, etc,the situation would not have turned into what is now a family fight and hurt feelings. My sister and I are very upset with him for causing this family fued. I refused to go see my mother because I know it will be nothing but a chewing out by her like when we were kids. I am 60 yrs old, I have had enough of her controlling, disrespectful, painful words that she can dish out and I refuse to take it anymore. I am very upset with both of them not understanding why we took what few items we have and accusing us of "stealing." There are at least 2 more pickup loads of mom's items left in the house, so we did not "clean her out" as my stepdad told mom. They get these ideas in their head and there is no changing their mind nor reasoning with them.
My sister and I are ready to cut ties with both mom and stepdad completely, I am so hurt after spending weeks at their house (40 miles away) getting mom's affairs in order (her bank accounts, cancelling her cell phone, getting her in the nursing home, taking her to dr appts when she was still at home, etc.) and this is the thanks I get? It is a big slap in the face. Do I wash my hands of the entire thing (including no longer being her Power of Attorney), walk away and move on with my own life? My husband is just as hurt as I am and has been very supportive to myself and my sister. I would appreciate any advice.