Your sister sounds like my brother (minus the cosmetics— his focus is on other things). I can deeply relate to your experience.
I'd highly recommend the book "Hikikomori: Adolescence Without End" by Saito Tamaki, translated by Jeffrey Angles. First published in 1998 it describes the "hikikomori" social/psychological phenomenon, and ways treatment has been approached. Ultimately, Saito observes that nobody can "fix" the individual hikikomori directly— therapy must be multi-faceted, continuous, and ongoing, focused on reducing stigma and shame. And for all that, may ultimately not be effective.
I'd highly recommend the book "Hikikomori: Adolescence Without End" by Saito Tamaki, translated by Jeffrey Angles. First published in 1998 it describes the "hikikomori" social/psychological phenomenon, and ways treatment has been approached. Ultimately, Saito observes that nobody can "fix" the individual hikikomori directly— therapy must be multi-faceted, continuous, and ongoing, focused on reducing stigma and shame. And for all that, may ultimately not be effective.