Has he always had difficulty sleeping, or only in the past few years?
What was his line of work? In my experience this sort of sleep patterns are often part of post-traumatic stress.
Does he know he talks in his sleep and can he remember that he has dreamed or what he has dreamed?
Has he consulted a doctor about it? Can you get him to do so?
He can't continue to risk hurting himself at night, and how do you get any proper sleep with this going on?
You might just get him to a doctor by telling him that your health is suffering due to a combination of broken nights and worrying about him!