As an artist, I think it is a fair price. 4k for an original is not bad. It is all about exclusivity and perceived value. Once he sells it, it is gone. Now, if he sold a limited edition print of the original (like I do), he retains his original and everyone gets what they want at a more reasonable price.
I was offered 4,500 for an original that I produced about eight years ago. I declined the offer (my wife thought I was nuts, maybe I was/am) as I do not sell my originals. But now that I have the original, I can sell 150 limited edition artist's proofs, signed and numbered, for 100 bucks each. You can do the math and I still retain the original. It is about creating something from the heart with passion and sharing it with like-minded individuals.