Sad Corgi

You should tell them to go outside (away from other people). Sunshine is good for your immune system.

If being outdoors isn't possible a vitamin D supplement is about as good.

They can’t. One is stuck inside and the other has been paralyzed for 6 years now

I guess the best thing to do would be to get them near a window. Healthy foods also help.

UVB rays from sunlight produces vitamin D in the skin. Most glass windows block a significant amount of all the UV spectrum. A vitamin supplement will work as well or better.

See if you can open the window, but if you can't, vitamin supplements should be pretty good.

One of them recovered, the other one died.

Also one of my teachers tested positive

Know that it should be fine. Unless they have a weak immune system or are at risk, they should come out ok.
And do you know what always helps with everything?
Dog pictures. Or dogs. Just go to a shelter and ask to pet all the dogs. Thats my expert advice
I hope they get better soon

look at cute doggos