There is one more thing that I would consider. If you do go forward with the contact and go to see her, (and I agree with the others that yes, you should), I think that you should take her some small modest gift, something in the nature of a "hostess present", something that she can look at afterwards to remind her that she has finally had a family visitor.
But ... you, at this point, don't have any knowledge of what her disability is, so I would also write separately to the care-giving organization asking for advice in that line. If, for example, they tell you that one of the high points of her life is the weekly visit from the therapy dog, a Golden Retriever, then a calendar with pictures of Goldens or puppies would probably please her. On the other hand, if she is also diabetic or unable to feed herself, a box of chocs is not a good idea. See what I mean?
Cheers,
Westoe