Agree - 70 isn't old, young T's have their own issues too.

Enjoy what you can take away from this experience and relationship you can. Hope instead for enough of a recovery to become less dependent on therapy (Instead of planning for a lifetime of therapy, have some hope this won't always be the case). When the time does come that her practise comes to an end I am quite sure she will do everything she can to find appropriate placement for her patients.