Don't forget that he is a businessman, and he is also the richest man in the world. If he were stupid enough to sell his fortune at a loss, he wouldn't be the richest man on the planet.
Based on price averaging, it can be inferred that Tesla lost money in the most recent bitcoin sale, but we don't have specific data for their bitcoin buy orders so nothing can be confirmed.
Rather than a businessman, he's a genius guy who has the ability to make money out of anything. He had practiced that for years and stays on the top. Now too it seems like ha haven't sold out of loss. There is a news into circulation that Musk have sold 900+ million worth of bitcoin and there is no perfect data on the same. This could be a play to test the market and enter at a lower price to profit through further tweets. There is no big movement from the common people as they've well understood about Elon Musk on cryptocurrencies.