In Pakistan, according to Wikipedia, there are blasphemy laws which can even result in death.
In the USA, where I am, we have a constitutional right of free speech, which does extend to children (all constitutional rights extend to every citizen). Although there is some political and legal confusion around these rights, generally children can say nearly anything without any response from authorities.
The question is: "What (and why) are some healthy ways to control the actions of a child (young adult), when parents are not present (e.g. at school) and the child may not completely internalize the seriousness of the matter at hand?"
This question is a rephrasing of an original question, which is linked at the end of this post. The following is my consideration of the question.
If a young child is playing with something dangerous and they do not comprehend the danger, as a guardian, it's easy to overreact and cause an emotionally painful event.
One does not desire to foul a young person's fire (no matter if it is personal, political, religious, or ... in nature) with unnecessarily harsh or restrictive conditions. However, it is important that this vigour be realistic in nature. If it isn't real, it is in fact pretend and does not need to be respected.
If it is real, your child may be someone who is unafraid to speak his mind and seek real answers when presented with, in his mind, an insufficient explanation, and might be very successful in his adult life due to this.
Since the original question is a serious matter where the mother is concerned about the Pakistani law, I would suggest keeping the child at home / homeschooling until his life is no longer at risk.
I thought this was a very well formed and appropriate question, but it was closed, apparently without consideration to the seriousness of the subject. How to stop my 8 year old son from doubting and/or speaking against the existence of God?