Downgrading to a dumbphone

I am looking for a dumbphone (i.e. capable of calling, texting and little else) that would work with the Sprint SIM card inside a Samsung Galaxy S3. Reason? This would be a "punishment device" of sorts for my teenage son who's been using his smartphone so much lately that it started affecting his grades. We do need to communicate with almost daily after he gets out of school, that's why I am not simply taking away his device, just trying to find a "dumb enough" replacement. In fact, if it can simply call and not even text that might be enough.

The trick is to make sure it will recognize the SIM card and will work with it. How would I do that? In other words, what sort of specs should I be looking for in the dumbphone?

Thx