Parden my ADD mind as I go through some scenerios here...
If she has a good support system at the hall, expect others to offer to pick her up for mid week meetings. The elders might even enlist someone. Be on the on lookout for busybodies...
I also wonder, not knowing anything about the situation... if this is just an excuse on her part to not have to go. She'll go to Sunday meetings for awhile, and find excuses to miss some of them even. Is something going on that has discouraged her?
And on that thought, I wonder this... how many elderly ones are discouraged about the whole 'overlapping generation' thing. If they're a certain age, and they start to realize that they aren't going to live to see 'the end', would that prompt them to slow down?
And as I keep sidebarring... who needs the Kingdom Hall anyway? When you've got 24 hour JW TV, you can get instant spiritual nourishment without even having to put your pants on. Forget putting on a suit and driving in the dark thru a bad part of town to a KH...
Anyhooo... this is the perfect opportunity to use this new free time to get her interested in other things. Together you can enjoy TV shows, or maybe cooking together, hobbies, anything that keeps her occupied. Choose activities that you know interest her, and maybe never had time for before. After awhile, you may find she'll want to share her Sunday mornings with you doing her new favorite activity, instead of going to the hall.