Regarding MC and your h seeing a therapist, while this seems to be a common sense approach, very few therapists really understand MLC. I found even the ones who said they did, really understood midlife transition but not crisis. And those are two different ballgames altogether. The former is a guy who is mad he's not making more money. The latter is a person who goes off the deep end.
People in MLC are very fragile as you have seen. If caring for a dog is too much for him (which is typical for a MLCer) how the heck can he handle much of anything else? This is why we have to get finances in order and protect ourselves ASAP.
They give the same speech, they all become the opposite of who they were but from there they all take different crazy trains out of the station. They will do what they need to do to ease the pain. And because they have poor, low functioning coping skills they have to figure out how to ease that pain. But first they will run from it all, blame the spouse and do anything to feel better.
Focus on you and your kids. He's going to need eons of time.
Me 41, H 47, M 15 yrs, S11, S13 BD 1: 11/4/14 we work on it; really I pretzel myself BD 2: 3/31/15 H goes down to "dorm room" 8/15: H back to MBR 10/15: H back in dorm room 1/18: H files, now divorced