Stuck in a bad mood

My hubby has a mental health illness (that he takes meds for and sees doctors and get lots of support) and he goes through ups and downs a lot. Almost every day he’ll get in a bad mood at some point (like just not feeling the best, kinda down) and can’t get out of it. Kinda stays that way for the rest of the day.

Most of the time it’s just random, but lately I’ve been noticing it’ll happen after we have a conversation that may not be the happiest (just small disagreements that get resolved almost right away or just serious conversations that may not be fun). That’ll get him in a bad mood and after that he can’t get out of the bad/down mood.

At least for me, when I get in a bad mood, I just have to let myself be in that bad mood and I’ll get over it if I just let the mood run it’s course. But that doesn’t work for him. He stays in that mood. What can I do to help him maybe learn how to get out of the bad mood? Any coping skills? Sometimes we’ll get out of the house for a change of scenery and it sometimes helps.

I keep telling him he/we need to find some coping skills to help him when he gets like that, but easier said than done right 🤷🏻‍♀️ it’s hard when I feel like I can’t get him out of a bad mood when I’m trying 😕