I agree with remar. I hope he's not trying to taper off these meds himself? He should discontinue the medications under the guidance and supervision of the prescribing doctor. What disorder is he being treated for?
As for the e-mails, can you elaborate a little? Who all has he sent e-mails to and what exactly is he saying in these e-mails? What's his reaction when you ask him about it? Have you tried to have a calm discussion with him about this?
Yes, this could be a possible side effect. Is your husband working with his Dr on a tapering program? If not, he really should be. Cutting back on 3 meds at the same time is a big deal. Can you say why he's cutting back on all of his meds?