Much of this is in the 'Sticky's' at the top of the topics page.
Go there for in-depth definitions.

The diffuse part just means affecting different areas. No mention if it is polyneuropathy - more than one side-both sides as in both feet, both legs etc.......or mono neuropathy- affecting one hand, foot, arm, leg, etc..

Sensory fibers are touch, cold, heat, pain (pin prick).
(presumed lessened than 'norm')

Axonal - regards affecting the axons rather than the neurons and not the myelin sheath that covers the nerve cells in large fiber and some small fiber nerve cells. The smaller cells do not have the protective myelin sheath.
No mention whether it is considered to be small fiber ( the 'skin punch' test is the 'Gold Standard' to determine this).

Motor - affect the ability to move, walk (gait), stretch, bend, grasp, reflex responses to rubber hammer, etc

All of these seem to be either affected, or diminished due to his neuropathy, after the EMG exam.
Usually a nerve conduction velocity exam is given at the same time.
One is the electric zaps, the other is needles like acupuncture ones- inserted into the nerve areas to see if the signal pathway is being affected.