Manuel, Andrew
I did an upgrade install to ArcGIS Desktop 10.2.2, including the 64-bit background geoprocessing extension. And then did a clean install of the 64-bit ArcHydro Tools (ArcHydroTools_x64.msi v10.2.0.40).
A cursory run through the menus and functions showed no issues. So, unless Christine or another from the Water Resources team suggests otherwise--should be OK to use with the Desktop 10.2.2 release.
Stuart