[nickr]

1. Not necessarily better. Hub can do Android or OpenELEC or LibreELEC. It is versatile
2. Don't see why you'd have any issue with USB HDD's under Android or OpenELEC/LibreELEC
3. Powered can help; depends on type of external HDD. Some work just fine with power via media player's USB
4. Honestly, depends how old and tech saavy you dad is (not saying he needs to be, but every bit helps). My dad is 80, and he has trouble with anything that doesn't involve a simple channel up/down type functionality. I set-up a non-Kodi WD TV box for him with movies on an attached USB HDD, and that turned out fine. Used movie posters view for navigation. That's it. With Hub, if your dad is okay using remote to open WeTek Media Player and navigating to 'Movies' you set-up for him, that would work

Thoroughly disagree with your 1. Hub hardware is far superior to the Play.