How did the twin brothers and sisters landed on the coast of Illyria and how was Viola consoled of her brother's loss?

Sebastian and Viola are shipwrecked. Viola land in Ilyria by accident and takes a position in Orsino's household. In order to do this, she disguises herself as a man. Sebastian is saved by Antonio, but he does not take on a disguise. Thus, over the course of the play, Viola and Sebastian are often confused. The captain consoles Viola by giving with the hope her brother is still alive.... she survived, so might have Sebastian.