It's quackery but harmless, I agree....but you might want to check what your lad is taking and if it has an effect with anything that he may have been prescribed as there are some dangerous herbs out there in the wrong potency. (Appreciate that homeopathy remedies are normally diluted to crazy levels but I wouldn't want my kid taking Senna, even if it was diluted to one drop in a hundred)
Ones to watch out for are - Chaparral, Coltsfoot, Comfrey, Ephedra, Lobelia, Pennyroyal, Senna, and Yohimbe as they all contain NGDA which can cause liver damage.