Suppose what I related about medical patients in my comment below is
true.

Suppose that it’s true that, in general, patients with an unrealistically high expectation of recovery do better, medically, than those with a more realistic expectation.

Now suppose that you are a doctor who believes this to be true, and that you want your patients to have the best chances of successful recovery.

What should you tell them about their chances of recovery? Should you give them the most accurate prognosis you can, based on the best information you have? Or, should you lie and tell them that their chances of recovery are better than they are, if the proper treatments are diligently followed, because you believe this will lead to better results?

What would you want your doctor to tell you?

I think that many people might prefer to be lied to. They wouldn’t mind being misled if it would be likely to lead to better results. If this is so, perhaps they could have a prior arrangement with their doctors that they want to transfer this responsibility to them.

I would want the truth.

I think it has to do with respect for my autonomy as a human being. It’s up to me to decide how to handle the best available information, not the doctor. Just as it would be wrong for the doctor to impose a procedure on me, without my informed consent; it’s likewise wrong for him to decide what I should and shouldn’t know about my condition. Yes, he’s an expert and has more training and knowledge about these things, but it’s my life. He’s a trusted advisor, not the master of my life and health.

By the way, children are people too! And they, likewise, deserve the truth and consensual advice (rather than lies and force) from their parents.