There is nothing wrong in writing qur’anic verses and prayers from the Sunnah with saffron in a clean plate or papers and then washing it for the sick person to drink it, provided that the person who undertook this is known to be of a religious character.
Some of the salaf (pious predecessors in early Muslim generations) were reported to have done that as Imam ibn al-Qayyem pointed out in his book Zad al Ma`ad.