Unexptected forearm rotation caused by transform axis not aligned

Hi! I downloaded a human 3D model cause in my application i have to move a human arm. Then i made some rotations and i saw an unexpected movement of the fore arm around X-axis and Z-axis, in my opinion it happens because the reference axes of the fore arm are not aligned with the fore arm (as shown in the picture)

And even rotating around the y axis in order to align the fore arm does not solve the problem cause the axis rotate too (stupid me!). So i thought that there was something wrong in the rig and i saw that in order to have the model in T position the fore arm Y-axis is rotated by 20 degrees. That's the point of my problem? And how can i solve that? Thank you all!