My parents both ditched their iPhones before the plus came out due to size and eye sight. They haven't gone back to an iPhone plus.
Video Conference: Best in class I would say is Google Duo. It is dead simple and works across all devices.
Apple's weakness: Siri. Now as an adult I don't use voice commands much but both my two youngest 11 and 7 and their friends use voice commands all day long (On my computer and Google Home). I see this being a big issue if they don't fix this in about 3 or 4 years. We see a big upswing in voice commands and Google's recognition has a 95% recognition rate is about on par with humans ability to carry a conversation. http://www.kpcb.com/internet-trends