Obeying one's father regarding irrigating or selling Qat

Q 2: My father owns a farm on which he grows Qat (Khat: leaves and buds that are habituating stimulants when chewed or used as a tea), alternating the rows between Qat and corn. He orders me to water the corn and the rest of the farm, but I refuse because the Qat is planted along with the corn and because I cannot water the corn without the water reaching the Qat. My father sometimes not only orders me to pick the Qat to sell at the market, but also sometimes orders me to sell it myself. Sometimes I obey him and at other times, when I try to explain that the plant is prohibited, he becomes angry. I love my father and wish only what is good for him and pray that he enters Jannah (Paradise). Please take into account that my father observes Prayers regularly. But the problem of Qat in Yemen is a public concern.My question is: Is my work permissible? If not, please direct me and advise my father so that he may be persuaded if he sees and reads my name as the inquirer, especially if the Fatwa is from the Permanent Committee and he sees and reads the signature of the Grand Mufty.I kindly request from the eminent scholars that they advice my father, the people in my village and especially the people of Yemen, in general. I also hope that you supplicate to Allah to guide my father to the Right Path. May Allah reward you with the best on behalf of all Muslims.

A: It is impermissible for you to obey your father in watering the Qat because it is prohibited, as it is also prohibited to sell and receive money for it. It is impermissible to obey anyone in disobeying (Part No. 11; Page No. 67) Allah for this involves cooperating in sin and transgression.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.