Where do I start to get power of attorney so I can speak for my husband?

You start by getting an appointment with a lawyer to draw up the necessary papers, POA for both finances and health. You might want to make sure your own affairs are in order as well and consider any changes you may want to make in your Wills. A diagnosis of Alzheimer's doesn't immediately make someone incapable of signing legal documents, he only has to be able to understand and approve. And get him to approve your access to his health records with his doctors as well.