It isn’t the key phrase is “command mirror” going into a window and manually controlling a toon is direct input to a singular world of Warcraft client compared to the old methods which had a direct input to one client then software or hardware mirrored the commands to other windows designated. In the case of hardware, it was the only thing running on the machine and all the machines would have the same mouse / key movements if things were copied. If the program only affects windows keybinds then it should be ok, however, it’s third party software so if he was using it for that purpose or not blizz could flag it if their anticheat set it off.
Edit: Looking at the basis of the software, it is originally designed by windows for use in their windows machines although in 2019 it did go opensource, therefore, I would try to avoid it… just to be safe. Opensource software can be a recipe for disaster. It’s not the original piece, derived from the original pieces and deviated from the original intended design potentially. You do not know what someone could have slipped in there with the open source… least from what I can gather information wise about the software discussed.