Our family history is that William J.D. Alexander went to live with his neice Wells Alexander(married to John W. Bain and dau. of William's brother Thomas Crawford Alexander) sometime after 1910. Dr. William is shown in their household in San Antonio, TX in the 1920 Census. His Texas death certificate under William James Alexander says he died senile on 10 Mar 1927 from a cold in Center Point, Kerr Co. TX which is near San Antonio.
Hope this helps.