I have a nexus 7. It's a great tablet depending on what they're going to do with it. Just browsing the Internet and a possible video call here and there, I'd recommend it. Plus it has trim... The software feature that should keep it running smoothly for whatever life they want to get out of it. All the play store apps that I've wanted to use work great on it too. Fairly simple interface since it's running stock Android too.
Either that or an older refurbished ipad from apples website.