You can ask anything about him but the hospital is under no obligation to answer your question. We have HIPPA laws. This law prevents any doctor or hospital from providing health information to the parents or any friend about the patient that is under their care.

In the United States a hospital or doctor can be sued for giving this information to anybody unless the patient gives the ok by a letter saying that his parents or anyone else can get his confidential information.

Even a doctor needs to get a subpoena to be allowed access to confidential medical or mental information.
This is why doctors or hospitals make you sign a permission slip allowing his/her information to be given to whoever they feel needs to know.

A person’s health records are protected from being disclosed to anyone. If for some unknown reason you need the patient’s medical information as a parent or friend. The patient must approve it by signing a form.

By telling his parents you are giving the patient’s confidential information. The hospital or doctor must have consent from the patient. Only law enforcement can request the information for whatever reason and possibly get it. It’s a slippery slope. Health charts belong to the patient unless the doctor is given consent to give someone or another doctor your information. Doing so is against federal law.
I suggest you have him tell his parents not you. What would be the reason for divulging this information to his parents. If he is a minor the parents need a court order to get his information.