The Healing Summer by Heather B. Moore

Summer 1981
At the age of ninety-four, Maggie Howard’s final wish is to return to San Francisco and find out what happened to the young man who saved her life in 1906 after the disastrous earthquake and fires that devastated the city. They’d been trapped beneath a collapsed roof for hours, injured and unable to call for help.
The morning of their rescue, Orlando Gallo promised he would find her again. But Maggie hasn’t seen or heard from him in over seventy years, and now, widowed and childless, Maggie hopes to leave her estate to Orlando’s descendants. She invites her neighbor, forty-year-old Jo Sampson, to travel with her, and as the two women return to San Francisco to track down Orlando, they form a strong bond of friendship and healing that transcends time and place.