My Ammi call my dad with his name.. also says him Sain and sometimes poRha 
Its not tawanje baba, its Pinhay / babhay in typical Sindhi while discussing something about their father with children. Our Naani refers to Naana as Naanhe (Your naana) and Dadi (Amma Wadi) referred to dada as Babhay Wadho.