Is Android itself a good decision? Apps aren't as strongly sandboxed, much more data gets collected (by Google, but that means an account compromise is much worse than it would be otherwise), security overall is worse.

I remember when I had an Android phone and I took a peek at Google's personal-data dashboard at one point. It had a line drawn on the map tracing my every footstep for the past several years. Vacations, commuting, visiting friends. Everything. It was neat at the time, but is a nightmare scenario for this kind of thing. You can disable some of that, I think, but Maps will constantly bug you about turning it back on.

At the very least I'd steer them away from installing any apps that don't come from major global corporations. There's a ton of malware on the Android store, especially games, and it's not hard to imagine some of it collecting data to sell on the black market.