Tough one. My parents are in their 70s and I have talked to them a bit about bitcoin. They are not against it but are scared of technically screwing it up. I hold some on their behalf. I wouldn't approach it from the perspective of why they should adopt bitcoin but instead why it is important to you and your generation. I don't think many 70 plus people are going to get orange pilled who aren't either technically sound or understand monetary theory, economics etc.