I have not much to say that will help you. I think it is good that H is sharing his issues with you. It is great that he is comfortable enough to do so. Some depressed people share such stuff because they are feeling sorry for themselves and want others to do so as well.
In your place I would probably review my validationphrases to be sure to have appropriate ones if he opens up again. Maybe you are better at validation than me, but no harm improving it. He needs to feel heard.
Realising he went through such tough times and is again can only help you.Feel empathy for him but not pity.
Also it has to help to know there is a reason/an identifiable cause for his mlc. Most lbs never know why this happened.
Best wishes
R 25 years M 14 years S11 & S13 Working on it alone since Oct 2014 M in trouble a lot earlier (~2 years) Feb 2016. 1st R chat in a yr. Next R chat Aug'17 Still together