Am I missing something?
The M just indicates if that particular Account has any characters associated with it. It's merely a rough indicator. If you know that he should have characters associated with the account, head to Admin > Characters, and edit the appropriate character. The very last option is "Associated Login", choose the appropriate login name (in this case, "fathermike"), and click Save. That'll associate his character with the account.
The lack of an M, like I said, is just an indicator of whether or not that particular account has any characters associated with it.