One year visa for the technical training

He can try to apply for an F type for that, and he can apply for the one-year multiple-entry F type, but I’m not sure if it can work in the end. If possible, you are advised to contact with the embassy of China and consult about that.
If he can do that on an F type, he needs to prepare those documents including his passport and copy of its data page, a bareheaded color photo, an application form, an invitation letter of duly authorized unit, an invitation letter from your company, an financial support documents. Afterwards, submit the application to the embassy of China to apply for the F type.