It depends on what you mean by preprocessed data.
If you are referring to the preprocessed images no.
BRAPH can only deal with numerical values corresponding to time series of each ROI in an atlas or it can deal with connectivity matrices, both of which I think you can get from CONN.
If you’re going for the matrix option, I would suggest saving the weighted matrices because we provide more options for thresholding the matrices. We also provide a lot more options for the graph theory analyses.