Has your husband actually been diagnosed with Alzheimer's? If the police took him into custody for assaulting you, and this is documented, you may be able to have him committed to a nursing facility if it's documented he has Alzheimer's and attacked you.
Your story is similar to something that happened to someone I know. Her husband was diagnosed with Dementia. He tried to strangle her one morning without warning. A neighbor saved her life by calling the police. He wound up on the lock down ward of a nursing home and spent the last several years of his life there.
You might want to consult with the doctor involved this case, plus a lawyer if a court order is needed.