How does Jane Eyre save Rochester's life?

At the end of the novel, Jane returns to Rochester. She is shocked at his appearance and finds that he has been left blind and one of his hands is amputated because he was severely injured trying to save Bertha Rochester during a fire. He now resides at Ferndean, about 30 miles away from the blackened ruins of Thornfield. Jane arrives, and, as they talk, Rochester "stretched his hand out to be lead, I took the dear hand. . .I served both for his prop and guide." Thus, Jane's return probably saves Rochester's life because he now has someone to support and even guide him. Eventually, she marries Rochester and they have a child. Even though she is considerably smaller than Rochester, they have become equals in strength of character and intellect.