The first thing I told him was the meaning of BTC and the reason of creating Bitcoin by Satoshi Nakamoto, which was to remove 3rd party control of funds.
And also the risk that involve in investing in Bitcoin. I told him the example of the present bear market. "Now if you invest in the price rate of $16k and the bear decline again to $10k or below which was predicted. And you want to use your cash at that time, then you become a loser in the investment. But if the price goes up to $20+ price then you make profit from the investment. Then I told him to go for a long term investment and he accepted the explanation and used $20 to start the investment. He is still under my coach.
Just interesting though that a pastor, a man of God is very interested on bitcoin?
Anyone can be a man of God, not only a pastor, more often than not, many who suppose to be a servant of God often take advantage of his follower and exploit them and suck them dry . ( I am not talking about the Pastor friend here, just stating my observation in general)
Pastors has still personal needs, in a small community, donation of the followers may not be sufficient for the pastor so he is looking for another way to earn funding either for his personal need or for the church's needs. And possibly this time @OP had influenced his pastor friend to try Bitcoin investment.