Amazons assistance for account issues to organizations if an employee did anything individually is honestly horrible.

They treat it like the organization is attempting to commandeer someone else's account so all the privacy protections you expect for your own stuff is applied no matter how much you can prove it is not some other individuals account.

The best part is the billing issues that arise from that. In your example, if the previous engineer logged into that account (because they can) and racked up huge costs, assuming that account is getting billed or can be tied to your client, Amazon will demand your client pay for them, while at the same time refusing to assist in getting access to the account because it's someone else's. They hold you responsible, but unable to act in a responsible manner.