Admittedly having done no research on this, it's no longer his benefit, so I would think that not only is the plan not obligated to provide the information, it would be wrong to provide the information. What if he asked whether a co-worker had started receiving his/her benefit? (Although what possible adverse ramifications could there be if the plan stupidly did answer his question?)
And since the husband isn't making a claim for benefits, and he hasn't been denied anything (except information not applicable to his benefit), I don't see how the claims appeal process is possibly implicated.