I thought so too. But then why is it written that his older brother accompanied him on the train ride. Yes, I have OCD.
"The older brother who accompanied Mr Brierley on the train ride was found dead on railway tracks."
I think this is right. Also, it's quite sad to consider the older brother's fate. After he lost his little brother, he may have spent the remainder of his life searching around the train station for him.
Other writeup of the story has the same mistake. First "he is separated from his brother and boards a train", later "the brother was accompanying him on the train ride".
Given the tendancy of Indian rail lines to be overloaded (and for beggars and hobos to hang on the outside of trains or on the roof/undercarriage), is it possible both are true? That he was seperated from his brother, but both somehow got on the same train and his brother 'fell off' somewhere along the way?
Pure speculation, but it might put your OCD at ease.
He got separated from his brother and subsequently got lost.