Shaina didn't die... she left Prachi in damyanti (akshay's mom's) care.
Night girl, if you remember, damyanti said that Shaina, Akshay's dad, and Mamta all left her alone. She didn't say they died... we can assume Akshay's dad died, but Mamta didn't die, did she? So why would she include Mamta's name in that list? 😕 So, Shaina didn't die, she left them, though.