Sr. Caroline Ngatia of the Assumption of the Blessed Virgin Mary Sisters of Eldoret shares breakfast with the street families in Nairobi, Kenya. Her center, Kwetu Home of Peace, accommodates homeless boys ages 8 to 14 who are rescued from the streets and slums in Nairobi and inducted into a process of reintegration. (Doreen Ajiambo) The goal is as simple as it is complicated to achieve: Shift the care of children from institutions like orphanages to a family or family-like environment. Catholic sisters in three African nations — Uganda, Zambia and Kenya — are leading the...