My brother lost my phone and he wants to retrieve his gmail account because of his impo...

My brother lost my phone and he wants to retrieve his gmail account because of his important contacts. We are trying to retrieve the account using his phone number but the thief keeps rejecting the two-step authentication process. We are worrying about the contacts because the thief might call them and ask for money. He already had access to my brother's bank account, from **,*** balance to zero.