My DH is a SAHP by choice to our 11 and 9 year old DC. This means he is not looking after children during the day, is socially very isolated. He no longer sees work friends. He spends almost all his time alone.
He seems to be having some sort of prolonged breakdown. We went out with friends last night for dinner and he proceeded to pick a huge fight with them, to get upset with the state of the world, the government, poverty, you name it. He was ranting, would not let anyone get a word in, was almost uncontrollable. Our friends were Uber polite and sort of humoured him but at one point they observed that his argument did not hold up (he was arguing in favour of communism) and he suddenly stood up, shook hands with the friend and said, "I will never see you again, I can't be friends with someone who holds such views, goodbye" and stormed out of the restaurant.
Yes, he had drink too much, but this was not your common or garden pissed person. This was existential rage.
I followed him because he had the car key and I was afraid he would drive home. I am not sure if he would have done so (leaving me in the restaurant).
In the car, I drove, he said something like "I cannot tolerate the sycophancy, I cannot stand the hypocrisy. There only way I can cope is speaking my truth, calling out bullshitters [ie our friends] it is the only hing that makes life tolerable for me."
When I said hat statement worried me (his father committed suicide, family history of depression), he said "Don't worry, I will never commit suicide, I am at heart an optimist."
I am married to a man who tells me not to worry, he won't commit suicide. 
When we got home he was almost sobbing. He hates modern life, consumerism, mass market food. He is bordering on conspiracy theories about statins, Big Pharma.
I am so lost.
I have no idea where to turn.
Any thoughts?