You sound a lot like my late husband ā he was unpredictable- continually like an M-80 with its pin pulled. He could be in the best mood walking through the door from work and by the time he got to the back of the house to change clothes, he might be a raving lunatic to the point of making the one dog a nervous wreck.
He made the horses nervous, even on his good days so he only helped with barn chores and only in my presence.
He was not abusive and was great at tap dancing around anything sounding verbally abusive, but nonetheless, his verbal behavior was abusive. His snot faced attitude was why I stopped cooking years ago, because he complained about everything. I told him to cook his own food which he did but at least once a week he would throw it in the garbage because what he fixed didnāt suit him.
This man was not my sonās father, nor was he ever in the military, but I say all this because he had deep rooted anger issues over something early in his life and so do you. I am sorry but you remind me too much of life with late husband to give you any sympathy. My deepest sympathy is, however, with your wife.
It would be great if you could find qualified help, but sometimes those so-called qualified people are less Help than not doing anything.
Best wishes to you.