For calls, you can accomplish what you're looking for by using Fixed Dialing Numbers (FDN). This is a whitelist of sorts that is stored on the SIM card itself. FDN restricts all outgoing calls to specified, pre-approved phone numbers/contacts, but has no effect on incoming calls or outgoing calls to emergency numbers. To set up FDN on most Android phones, go into the Dialer (Phone app) > Settings > Fixed Dialing Numbers. You'll need to set up a PIN in order to configure the settings.
Here's more information:
As for SMS restrictions, that isn't quite as simple. You can consider a third-party text messaging app from the Play Store; there may be one which allows for similar PIN or contact-based restrictions. Either way, you'll want to hide the stock messaging application by going into Settings > Apps > All > [Stock SMS App] > Disable. This will hide it from the homescreen and app drawer.
Though I don't know the details of your situation, and I don't presume to know what the best course of action for you is, I would be cautious with trying to disable calling/texting functionality altogether. Leaving emergency number support intact is always a good idea.
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