Minecraft Java Says I need to buy it again

Hello! My friend just bought Minecraft Java edition and we're all very excited and happy. But there's a major issue. He logged in to the correct account but it's saying play demo or buy Minecraft. He already bought it and can confirm it. Me and my friend really want help, we've been wanting to play Minecraft for so long now. Please help! Any help would be SOOOO much appreciated. Thanks.