@MojangSupport My brother can't access his Minecraft account because the linked Microsoft account has been stolen. hackers have made it completely impossible to access the account. We have tried it with all existing systems but it is not possible. The question in the answers:

@MojangSupport Would it be possible to change the Microsoft account linked to the Minecraft account so that I can recover the game, even if we do not have access to the old account?

@MojangSupport We've been trying to recover the account for several months but, as I said at the beginning of the thread, it's completely impossible. (Note: the hacker requested €400 for the return of the account, and I currently do not have the possibility to cover his demands)