Complex sentence: Limited mobility kept both sisters at home, where Winifred wrote unpublished novels for Doreen, who was now terminally ill. Christine's medical problems increased, requiring that she move in 1989 to Resthaven, a nursing home near Stroud, and Winifred accompanied her.
Split into simpler sentences: Limited mobility kept both sisters at home, where Winifred wrote unpublished novels for Doreen during a terminal illness. When Christine's medical problems increased, requiring that she move in 1989 to Resthaven, a nursing home near Stroud, Winifred accompanied her.