He'll be interested when Bitcoin rises and makes headlines to the news, and will come to you with regret why didn't he listen to you and made purchase.
A friend of mine is not interested in buying Bitcoin even after learning about it.
Because according to him Bitcoin is a small number of people who have a lot of Bitcoin. They can easily go down on the bitcoin market if they want to.
Example: Cz. Craig wright & Michel Sailor etc.
Looking forward to the well thought out opinion of the experienced in this regard.
Although, he's correct in his own regard, market will go down if these people or other whales were to make market sell. But, we all know it'll recover, as it did before.
If he is really rich and has a stable income then the fact that he is not interested in bitcoin is not bad or he is wrong. You should not expect that one day he will regret not investing in bitcoin, with that in mind, it is like we are ready to curse someone if they know about bitcoin but do not invest in it. Don't forget that many people around you are living richer, happier lives than you without bitcoin. Bitcoin is just one of many tools that bring us money, and people have the freedom to choose what they want.
If they invest in bitcoin then we welcome and welcome them because we are of the same mind, but if they don't like it and choose something else then that's okay, as long as they are happy with their choice.