Upon reconsideration, yes this was bad advice. When I read he is on a "work visa" and in a bad situation due to job transfer problems, I automatically assumed he was dealing with the worst kind of employers waiting to exploit him. Clearly this is not the case most of the time.
So agreed, if he works for a good manager / employer, it is better to be forthright.
Whether or not to actually go with this approach is up for debate, but the terms of his engagement with his new employer are not in any way, shape or form his old employer's business. There's a reason so many laws exist to protect the confidentiality of such information.
So agreed, if he works for a good manager / employer, it is better to be forthright.
I rescind my advice.