Did you see the post below where the Convent was close to the areas I grew up in. Here is a link about Nuns. I thought maybe a nun could privatize her past and not let any one know about her whereabouts. Case Closed. I thought maybe mom decided it was better for her? One of the places she lived was at the Mission San Gabriel. My grandmother in Pasadena grew up in a Convent and her sister Mena was a Nun. Troubled times could offer a solution. Mom says no; I'd like to think that that would be solution and a good one. Grandma and Grandpa could of did a magic trick and legally made her disappear.
Too far fetched.