He should go for it. It will make or break him.
I don't think it would break him, even if he failed miserably. Obviously he'll face a pretty meager opponent. If he wins he'll get all the plaudits, but even if he loses he'll still make a shed load of money from the whole thing, and people will just say things like 'well he's not really a boxer', 'he did better then we all expected', 'he gave as good as he got', etc. The press isn't going to rip into him, and the fight will no doubt be very well managed by the referee, who will just call time if he risks being knocked out, or is in serious trouble.