If I were you, I would not have anymore conversations regarding prepping with this person. Personally I would LIE to him and tell him I stopped so he doesn’t spread it around that you are prepping. A person with this much personal conviction will never be convinced to change their mind. There is no reason to talk to him about it, his views are only one mans opinion. I believe the Mormons are requested to have food in storage so at least one sect is preparing in other than a spiritual sense.
We can have the perspective of, God has provided for us now in abundance, take advantage of it before the lean times come. Joseph had the Pharaoh store grain in preparation for the drought shortage why can’t we do the same.
“And let them gather all the food of these good years that come, and lay up corn under the hand of Pharaoh for food in the cities, and let them keep it.
And the food shall be for a store to the land against the seven years of famine, which shall be in the land of Egypt; that the land perish not through the famine.’
And the thing was good in the eyes of Pharaoh, and in the eyes of all his servants.”