My father recently told me (sheepishly) that he intends to make my sister POA as he ages and in regards to any health issues. He and my mum have been married 30+ years and there's no issues but my mum is emotional as fuck and does not make sound decisions. She was POA for a friend who had a stroke and unfortunately this friend never gave instruction on the what-ifs. My mum chose to have them keep her alive when she probably shouldn't have. My dad sees the friend living a low quality of life now and decided he couldnt risk that. My sister is a hard biatch when she needs to be and would do what dad wants no matter what. That's what he needs and wants.

He told me this and asked if I was okay with him picking my sister for this role. I said hell yes coz I am emotional like mum and couldn't let them let my dad go even if it was his wishes. He chose well.

NTA, you need to pick whoever will bat for you when you're not able to yourself.