Do I  have any other option, him being a minor? So how do I give him Bitcoin in a way that ensures he cannot tinker with it? I am concerned that he might try to buy more using my debit card credentials. Not saying he would, but just want to make sure.

Yes, good idea to teach him about Bitcoin. He is very financially aware for a 12 year old - indeed, I jokingly call him "breadhaed" soetoimes. I hope he may have a career in the City of London one day, if that is his inclination.