My dad is in his early 80s and has just made it clear that he expects me to 'help support' his wife if he dies first. For context, she is late 70s and fit and healthy but refuses to do anything or understand anything practical - travel, drive, make appointments, understand basic finances, how things work. They live very rurally in a massive house with no public transport. We live about 5 hours away and I work full time. I tolerate her and am civil to her for the sake of my dad, but that's it, as there is a lot of history (she split up my parents' marriage when I was late 20s and caused a huge amount of pain to our family). She has 2 sons in their 50s who are perfectly capable but one lives in Dubai and 'won't be able to help as he has work commitments' and the other is only a couple of hours away but 'not as good at that stuff'. I told my dad her sons will have no choice but to help if needed as I won't be doing it. He looked shocked. I am fairly sure I am not being unreasonable but not sure how to communicate this to him, as he clearly things I am.