Some Barelwis writing online have misquoted/misinterpreted a fatwa of Shah ‘Abdul ‘Aziz Dehlawi on istighathah.
The clear position of Shah Waliyyullah Dehlawi, his father, was documented in an earlier post; see here. The clear position of Qadi Thana’ullah Panipati, a well-known scholar and student of Shah Waliyyullah al-Dehlawi, and someone admired by Shah ‘Abdul ‘Aziz Dehlawi, was also documented earlier; see here.
The fatwa of Shah ‘Abdul ‘Aziz Dehlawi in reference can be found in his Persian fatwa collection on pages 33-34. A PDF of the fatwa collection can be found here.
The relevant section of the Farsi fatwa together with an Urdu translation and brief commentary can be found on pages 40-41 of Maulana Sarfraz Khan Safdar’s Itmam al-Burhan:
An English translation is as follows:
Seeking help occurs in two ways. One is for creation to seek help from creation just as a worker or beggar seeks help for their needs from the emir or king, and common people get the Awliya to make du‘a [for them] in making a plea to Allah ta‘ala for a certain need. Seeking such help is permissible in Shar’iah whether from the living or dead.
Second, in those things that Allah is specifically independent in (i.e. those things in which there isn’t even kasb from creation), like granting a child, bringing down rain, preventing (all) illnesses, lengthening life, and similar such things, while not having the intention of it being a du‘a or a plea that will be approved by Allah, creation is asked for help in them. This category is absolutely haram and in fact kufr. If any Muslim asks this type of help from any of the Awliya of religion, whether alive or dead, he will come out of the parameters of being a Muslim.*
As one can see, the distinction Shah ‘Abdul ‘Aziz Dehlawi makes is between matters that are ordinarily within the control of creation and matters that are not. With the latter category, it is not permissible to ask for help, while with the former category, it is.
When Shah ‘Abdul ‘Aziz Dehlawi mentions the permissibility of asking the dead for help, he is referring specifically to requesting them to make du‘a, which is not something Deobandis reject (see here). Barelwis who take this to mean it is permissible to seek help directly from the deceased, i.e. asking them to directly fulfil their needs and not merely asking them to make du’a, are distorting/misrepresenting what Shah ‘Abdul ‘Aziz Dehlawi said.
* This is the default rule but takfir of an individual in such a case may be averted based on ta’wil or jahl.