I feel for you both Sunflower2.
I've similar symptoms to your husband - long covid leading to shingles in my case - and it's a real headf**k to feel ok, on the mend and back to my busy, productive "old self" one day and then - could be later the same day - feel so exhausted, shivery and flu-ridden it's almost impossible to function.
I feel the impact on my family and it's so upsetting to have turned from being an ethusiastic go-getter up for doing stuff into a right miserable old cow constantly not wanting to go for lunch, out for the day, even going for walk with them which I used to love. Three big positives about the publicity now given to the condition is the research to try and get some explanations hopefully leading to a cure, the recognition that it IS a condition- really important to be believed rather than written off as it's all in the mind - and the support of a long covid19 sufferers group on FB.
If it's of any help to you and your DH I find stress, even silly stress like like running out of milk and needing to go to the shops, brings on a flare up and so I need to be very mindful to minimise stress wherever I can.
I wish you both the very best in dealing with this and, ending on a positive note, it has got better for me over time, hope it's the same for you.