Looking at his email, it looks like he left it up to you to read through the specification sheet to see if it will work or not.
Looking at the details on the encoder output, this is very poor and not even a connector accessible form the outside of the box, so will require going into the driver and connecting to the ABZ, but this is only 3.3V and also very unacceptable to esd and electrical noise.
If is was just a single ended encoder output with a good 5V signal and a connector on the outside of the box, then this would not be a problem, by connecting a standard board to convert from single ended to differential.
If you want me to put something on paper i can do.
It makes absolutely no sense to have a good driver like this being limited by no differential encoder output.