It is nice to here of such a longtime marriage. I am sorry to hear what has been happening recently. Your husband should have a neurological evaluation to rule out a brain tumor, which can cause behavioral changes. He also should be evaluated by a psychiatrist for any chemical imbalance in the brain which could be causing the symptoms of depression which would be treated with an antidepressant. Drinking alcohol is a strong contributing factor to depression and changes in personality, especially anger outbursts. Your husband's suicide ieation is of great concern and needs to be treated right away because it is a serious matter and he needs treatment. Make the medical appointments that I have recommended and let me know how he is feeling.
I wish you and your husband well!