If the person is mature and responsible, and they like to use the childhood name, I suppose that's all right.
But if a child is immature and irresponsible, whatever parents can do to help them mature and grow up would be a step in the right direction. Coddling never helps after about age two.
I appreciate you taking the time to consider my comment. I actually agree with you on the immature and irresponsible observation you gave in your comment. Thank you.