Lots of
and good vibes, OP. Times like these really do bring out the worst and best in people- and people do react so differently to stress!
For dh and me (+ 2 young adult children currently at home) this is not actually the worst time we've been through, so we already had a fair idea of where the pitfalls might lie.
Dh, though strong in a serious emergency (think, child in a coma), under less urgent circumstances has a tendency to go around sighing, which can quickly dampen down an entire household. Otoh he also knows that the reaction of his family to this is likely to be robust. Basically, it's about working out ways of pointing out his shortcomings gently so he doesn't end up painting himself in a corner. And for him to know that he needs to react in a way that doesn't make things worse for all of us.
I otoh get very sloppy when life is tough, careless, more untidy than usual, more withdrawn. Again, this puts stress on dh and he needs to be able to pull me up about it without making me too defensive.
We find humour works well for us. Also works well with teen children ime. You can get them to do the same thing, or even far more, by applying a lighter touch.
And it gets easier every time, because once something has been dealt with well and led to a successful negotiation, we both feel more confident and more inclined to trust the other person during the next disagreement.