Is there a stroke group in her area, if there iis find out the details, like could she be picked up and returned to her home, cost, what they do etc then, encourage her to go. She probably won't like it at first, encourage her to keep going, find out who runs it have a word with them, find out what they do, who goes etc then you will be able to chat about it.
It is possible she is slightly depressed about her lifestyle and can see little future, if she can go out occassionally it could give her the initiative to try to do a bit of housework even though she is restricted. See if you can contact her Doctor, see if he will pop round, ask him to make an excuse to call ie flu jab and ask him to see if he thinks she could be depressed.
Get in touch with Headway, the group that helps with head injuries, a stroke is a head injury.
Can you take her away for a weekend, there are lots of places where the disabled are catered for, it could give her the boost she needs.
It is hard when you are not near, but little by little you can make changes but there is no quick cure. Good luck.