I can certainly help you to understand what happened but getting it back requires that you prove to google that it is your account. If by "tied to his account" you mean that HIS email account is set up as the alternate email in the security settings it is going to be difficult or impossible to do. Google will consider whomever owns the alternate email address to be the rightful owner because that was the method set up to determine the rightful owner by the person who set up the account.
Is there or was there ever another method in the security settings that you have access to. Another email of yours ? a cell phone of yours ? security questions that you can answer ?