What can I do if anything to stop Dad?

Ok my parents divorced when I was a yr old. Well about 7 yrs ago my father was in a major motorcycle accident. After he got better he changed his poa from someone else to me (another long story). Well about a yr and a half later my parents reconnected and remarried. I know at that point my mom became next of kind and could help with decisions but it wasn't needed at that point. Now my dad has gotten dementia and is very combative (no he has not hit anybody) and verbally abusive to me and my mother (especially her) and hes spending money like everybody else on here on things he doesn't need blah blah blah. My mom has gotten to the point that she doesn't want anything to do with him even speaking and her health wont allow for a lot anymore (had a heart attack and stroke) but moving out is not an option financially. My question is how can I go around my mothers legal power to get to my dad to stop spending? I need help