Firstly, try social engineering. Either ask him about his honey moon (I mean, who keeps that a secret? "How was your honeymoon?" "Oh, I can't tell you, 'cause it's my secret question on my bank website." Thus, he's an idiot.), or just check his Facebook, MySpace, whatever, until you find somewhere he's told someone else.

You are going to have no luck talking to customer support, because they're not idiots. Some guy isn't going to all-of-a-sudden forget where he went for his honeymoon. This is some guy who's visited their website before - entered this information in himself. This is a bank website, not Gaia Online. They're not going to risk $3,000 because some random person is saying he forgot where he went for his honeymoon. Seriously.

Also, enjoy your felony offense and mandatory jailtime when you get caught.