How do I disable calls and messages on Apple Watch for dementia care?

I am wanting to get my dad, who has dementia, an apple watch so that he can see his HR, Step count, etc and so that we can see his location. However, I don't want him to be able to receive any calls or text messages. He has never had a computer or phone before so this technology confuses him and he can't be trusted on the phone anymore. Is there any way to take away the messaging and phone calling capabilities. His watch has cellular capabilities and is not attached to phone.

[Re-Titled by Moderator]

Original Title: disable messaging and phone calls completely