What other neuropathy could this be?

My husband had a major surgery 3 weeks ago, right before his surgery he noticed some pain in his left arm, slight, then about a week after the surgery the pain persisted and it aches fairly bad and now he has a numb patch on top around where you bend your arm and his thumb surface is numb and his wrist seems week. Then his shoulder started to ache. He gradually started getting bad burning patches on chest and torso and now some numb patches. They are like stabbing pains when he seems to move a certain way. He doesn’t seem to be weak in legs yet he is unsure if it’s just from having surgery and hasn’t been as active
15 years ago after a major surgery he developed burning tingling and numb patches and his legs went very weak and could barely walk, was on a walker. Had numerous tests and end result was what else could it be but CIDP so he was started on Ivig treatments for a few months and got better, took about a year to fully recover.
He went to the neurologist yesterday and she did an EMG study which came back good, she ordered an MRI of head/neck and we see her again on Tuesday. She didn’t want to do a spinal tap just yet. Does this sound like CIDP? I know there are a lot of neuropathies but she did say that Ivig treatments treat a lot of them. We are really afraid the insurance will deny them.

Thank you