Asak. I want to make my son eat khaq e shifa till aashura so that it heals him from insanity. How should I make him eat? Is it necessary to recite the big dua while making him eat it?

Our maraje allow such in a very minimal quantity like less than a pinch of salt even. And it should be done under health codes and laws. You don’t need to recite the Dua in front of him. Besides there is no specific Dua narrated by any authentic narrator.