The issue of souls returning back to this world has been explained by the scholars of Deoband. It is a possibility which has been occured to people of the salaf also. The same is repeated in the Ihya of Ghazali, Kitab al-Ruh by Ibn al-Qayyim, Anfas al-Arifin of Shah Waliyullah and in the Sharh of al-Fiqh al-Akbar by Mulla Ali Qari.
It can be understood in the sense of dead people appearing in dreams.
See this book by Ml. Sambhli which is an answer to the Barelwi book Zalzala: [url]http://islamicbookslibrary.wordpress.com/2010/12/16/barelvi/[/url] (p. 127)
None of this necessitates the shirki belief of the Barelwis surrounding tasarruf, haadir naazir and ilm al-ghayb. It has to do with kashf and ilhaam. Awliya are informed of certain issues of the unseen which is a form of karamaat, which is performed by Allah.
