She would not spoil his pleasure.

And then they discovered that after all he was not going very far away, only from the Nile to the town, and that Pharaoh had promised him liberty; he could visit his parents, and return to them whenever he so wished.

But he would no longer be the same child who went from them.

Mary reflected that that was the usual case with mother and son; the youth gave himself up more and more to strangers, and less and less of him remained to his mother.
There remained to her the memory that she had borne him in pain, that she had nourished him with her life; she had a claim on him more sacred and everlasting than any other could have.

But gradually and inevitably he separated himself from his mother, and what she would do for him, and give him, and be to him, he kindly but decidedly set aside.