He can get help for the depression too. Self-pity and excuses don't cut it with me. He can get help and he is responsible for doing that as a person responsible to the family, himself, you, the kids.
It sounds like emotional manipulation.
I have bipolar which has included some very long and nasty depressions and times of despair, that has never been an excuse to behave cruelly, violently or scarily towards others. I am still and always responsible for what I do and for managing my illness.