Joyce, this website is no longer active. Today was the first time I looked at it in, what, three months? and I'm not really sure why I did. But I did, and here you are.
Yes, a traumatic event can cause an Alzheimer's patient's symptoms to get massively worse in the twinkling of an eye -- one trip to the ER, a fall even if the patient isn't hurt, you name it. And yes, if that's what's causing your husband's current symptoms, he could return to baseline once the trauma is over and done with, although it can take time.
If you use facebook, I believe some of the spouses have set up a facebook group. The post just before yours on the New Members thread has the link. With luck, some of them may notice you're here and post information for you.
The Alzheimer's Association has a very large, very active message board with several different forums, one of which is specifically for spouse caregivers (the second one on the list):
https://www.alzconnected.org/discussion.aspx
You can browse without setting up an account, but you'll need an account to post questions (and answers), start threads of your own, etc. I'd recommend that you use the Caregivers Forum as well as the Spouse forum -- you'll need plenty of help. You can participate in any/all of the Forums if you want, but please be sensitive as to who might be reading what you say and how they may react. Warning: the Clinical Trials forum is full of misinformation -- the Association makes no attempt to monitor that forum for scammers. Don't waste your time, and don't believe anything anyone says on that Forum. Snake oil salesmen...