The most charming child shouldn’t be let anywhere near your brain.
Even if he doesn’t intend to do you any harm.
This is why.
Reading a book isn’t the same thing as knowing the tools.
Some little kids are smart enough to read every word in science textbooks. This does not mean that they understand everything about blood, neurons or your cerebrum. The person who wrote the book never met you. The author doesn’t know your exact needs. The person operating on you should know more than just what the words on the page say.
When you are inexperienced, you panic when accidents happen.
A child who paints the fingernails of a parent worries when the polish gets spilled. He’d be just as nervous if you gushed blood unexpectedly during your operation. You need someone who can be wise and stay calm (affiliate link) during a disaster.
If a problem happens, you might get blamed. Publicly.
What happens when a toy breaks in the hands of a kid? The toy gets blamed for being stupid, cheap, or hard. People don’t learn to see problems within themselves until they know enough to recognize what they don’t understand.
Working with a hypnotist who says and does those things is equally as risky. How do you avoid a person like that? You ask me questions in a reply.