One of the options they gave him was to take a leave of absence, therefore they are not requiring him to return to work. Look, I honestly understand how you feel. I am also someone who is vulnerable. However, there are just too many people out there who refuse to wear masks and no one is going to change their minds unless things get a lot worse than they are now.
Even if your husband is the only one wearing a mask, it will help him to some degree. It will be better than not wearing one.

