Ease her into it gradually.
Perhaps you need to have some event to go to together one Sunday, so that your husband will have to miss his visit to his mother that day. You could join him on the Saturday, to double up the companionship and help do the chores and shopping, and arrange for someone to visit on the Sunday - one of your husband's brothers is a good candidate!
While you are there, you could compile a list of what your husband does for her, and work on how it could be done without putting so much on to her. Involve outsiders in one aspect after another.
Plus, while enjoying the event, you would be able to tell him how much it means to you to be spending time with him, instead of on your own. Then keep organising more things to do together on a Sunday, while MiL is cared for by others. She will probably enjoy their company once she gets to know them.
Kate Garroway-Care at home costs
Is there such a thing as delicious ready meals?