FWIW, I grew up very close to my brother. We had a loving family for the most part.,... we were loved, fed, clothed, a house over our heads. Nothing extravagant. We all grew up and have had long marriages and happy drug-free children who are raising great kids of their own so far. All except for my one brother who made very poor choices later in life. He was estranged from me and my other brother for years, but my mom and sister stayed in touch. All pretty normal living.
What I am getting at now is that he has not kept in touch with my one sister like he used to and we are assuming he doesn't want to. Nothing happened, just no contact. He supposedly moved to Mexico with a friend to start a restaurant, but if he went missing, no one in our family would ever know because we have no way to find him and he doesn't want to be found........ just my personal life experience why family may not have known where she was or what she was doing all those years.