I don't have any specific answers for you, but I do know that a brain injury can mimic mental illness. When there is pressure on the brain, it can cause mood swings, including intense anger. It can also cause imbalance when walking, nausea and vomitting.
I would suggest perhaps trying to get your husband into a doctor to perhaps do an mri to watch for swelling that can cause this.
Also, if he threatens you or himself, and you call the cops, they will bring him to a mental hospital for 24 hours observation. That is the only way to "force" an adult into a mental hospital, but again, they can only hold him for 24 hours, after which point your only option is to appeal to the court to have them ruled incompetent, but the attending psych who sees them is the only person who can say, "yes, this person is incompetent and needs to be hospitalized."
hope this helps.
Stephanie