Can anything specific aid dementia patients in feeling better/handling auditory hallucinations?

Geriatric issues. It sounds like these issues are best approached by a geriatric psychologist, and a geriatric psychiatrist. Which is to say, you're looking for a psychologist and a psychiatrist both of whom specialize in geriatric issues, like the ones that you have described. State psychology and psychiatric organizations can help you find the best practitioners for these issues.