Can a durable POA be overridden in PA? My uncle is POA but I have been the caregiver of my grandmother for 8 years. She is 92 with Alzheimer's. She recently had blood clots and he refused to treat them. He is now saying ok to at home blood thinners but the damage is irreversible and already done to lungs and cognition.
I would think your Uncle talked to the doctor and weighted the pros and cons. Your grandma is 92 with Dementia and lung problems.
If you wish to make other decisions, as caregiver you may wish to apply for guardianship. Understand this can be an expensive process, and you well may lose as your Grandmother assigned this to her son.
As an RN the most and the worst complications I saw were do to blood thinners whether given in facility or in the home. They cause bleeds which can occur anywhere from brain to toe. Your grandmother has the right to not have a lot of heroic care and intervention if it has been her lifelong wish not to have same. Her POA may be acting in her best interests and according to her wishes.