If he doesn't see the point, he probably has enough of the wealth he has. He is happy without bitcoin. I agree with the
previous opinion, there is no need to impose your opinion in financial matters. You could lose a friend.
He may see the point, but judging by OP’s post, he fears that the bitcoin will depreciate, because a large number of bitcoin are owned by a narrow circle of people. Here it seems more like his friend's fear for the future of his wealth if it were invested in the bitcoin.
Bitcoin is not a tool that makes you happy.

Even for rich people, this can be useful just for preserving wealth. Because with wealth there are 2 biggest problems: how to accumulate wealth and how to save it. If poor people use bitcoin to solve the 1st problem, then rich people can use it to solve the 2nd problem.
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.
If he is not interested, then leave your friend alone. His finances are his problem.