In reply to Only a hill:
I disagree.
Installing and using apps on iOS and Android require the same level of technical skill (very little)
Apps on both require the same level of configuration, using similar (or near identical) control interfaces.
Modifying the basic system settings requires the same level of technical skill (very little).
I have never had to do more than install and use apps and the basic system settings on either iPad or Hudl.
The fact that I can use a wider range of apps for the things I want to do (media players), and delve into the Linux guts of the Hudl if I want to, and use a real file manager and device file store, or simply connect to network file servers are all bonuses for the Android platform. And I can use external memory.
I've had the Hudl crash. I've had the ipad2 crash. The Hudl1 is still as fast as it was when I bought it, and still runs all the apps I want, even though it's 'stuck' at Android 4.2.2). The ipad2 is now considerably slower than it was (ios5 to ios8 was the problem, but was necessary to run the new look UKC, IIRC...)
Facetime might be a clincher if your parents want to facetime with relatives who have iPads.