Is a $30 Million BCH SIM Swap Hack Possible in a Non-custodial Wallet?

A rumor has been circulating of an alleged SIM swap hack incident where a Chinese whale purportedly lost around $30 Million worth of BCH. The rumor stems from a now-deleted Reddit post of the supposed victim asking miners for help to recover access to his BCH. The victims added that he still has his private key and will be rewarding miners who will be able to help him. The victim clearly states that he has still access to private keys meaning he was hacked from a non-custodial wallet.