Suggest Remedies For Severe Hair Loss
More info on tests needed.
Detailed Answer:
I read your question carefully and I understand your concern about your son.
It would have been useful if you could have provided some more information on the tests he's had and their results, if you could upload some report from the neurologist consult might be useful. Otherwise I do not have much to go with here.
Regarding the numbness, I am assuming that the neurologists have examined him and physical exam was normal. Perhaps he's had some normal imaging exam and some blood tests as well. If that is indeed the case and issues such as multiple sclerosis, hormonal issues have been excluded then I would say that such generalized numbness is most probably due to anxiety, it commonly manifests that way. In that case psychotherapy would be more indicated if all has resulted normal.
As for the hair loss, again some info about the pattern, whether there is loss in certain areas or generalized, hormonal tests he's had etc might be useful. Might be simply genetically determined male pattern baldness, but hormonal issues must have been considered as well.
I remain at your disposal for other questions, but probably providing some more information.