I think by now you must have researched about it, but anyways, my dad had a similar syndrome but it's miller fisher. Guillain Barre - your antibodies attack your immune system, the paralysis starts up then goes downwards, ten miller fisher - the paralysis starts downwards then upwards, or I could have it wrong and must be the other way around. My dad had MFS exactlt two years, when he had an anti flu shot, it's a very rare allergic reaction to this shot, of course doctors wont tell you about it but if you searched the forums, you will see. It's a very rare allergci reaction to it and a very rare sickness. too bad my dad was one of those hit by those rare rare scenario. He had an anti-flu shot, then weeks later he had a flu, so the antibodies attcked the virus, but then the antibodies didn't stop attacking, and continued to attack until his immune system were being attacked too. The difference is that, I think GBS is more life threatening 
Sad to hear this story...

I would just like to comment...

Your father has a Cranial nerve Variant...
I would just like to correct your term "allergy".. Yes it's a form of hypersensitivity but It's not an allergy... Your father is genetically predisposed into developing this reaction to the vaccine, also depende din sa immune status ng father mo...
Other thing, Your father has MFS diba, so tama ka dun sa mula taas pababa (descending).... Siya yung naiiba,, Kasi dun sa ibang variant ng GBS mula baba pataas (ascending paralysis)-- ito yung karaniwan...
Sana maging ok na father mo... hugs...