If it's meant to be kept a secret, I'd keep that friend's confession a secret. I mean, if it's hurting nobody (not even him/herself), and if he's/she's comfortable with keeping it that wat, I'd support his/her decission. In the end, the person will come out/come clear or not, but it's not my call to make.
What would you do to convince the CEO and the board of the company you work for, to spend money on marketing/advertising to boost sales, instead of cutting costs (i.e. firing ppl)? (is happening as you read, in many, many companies)