Hi Dale and thanks for your question and pictures of your troubled boxwood plants. There seem to be two possibilities from your pictures. The first, and least problematic would be winter frost damage. We did have some really cold spells and boxwood can be damaged by this weather. If this is so, the plants should recover and you can simply prune out the dead spots over time.
https://www.newgenboxwood.com/blog/2020/6/1/frost-or-freeze-damage-and-how-to-manage-it

A more problematic possibility would be Phytophthora Root and Crown rot. I'm afraid this may be more likely, as I seem to see the bronze and the tan colors in your pictures. This happens if the plants have to stand in water over time and the soil has the pathogen in it. There are no cures, chemical or otherwise, only sprays that can slow the spread and must be applied by a licensed spray company.

https://pnwhandbooks.org/plantdisease/host-disease/boxwood-buxus-spp-phytophthora-root-crown-rot

As boxwood is a bit picky about its soil pH, you might also want to have a soil test done to see if that is stressing your plants into developing a disease or being more sensitive to extreme weather.

At this point, you can pretty much wait and see what happens in the next month. If the plants don't recover, there are some hardier alternatives to boxwood, but I know it would be a great loss. Check and see if your gardener can determine the difference between the phytophthora problem and frost damage, and you could also take samples into the local extension office to see what someone there thinks after looking at the actual plants and your pictures.

Good luck!