Is that they one where eye droops?Guillain-Barre' usually starts as paralysis in the legs and works it way up. If it gets high enough it can affect the breathing. Then you would be placed on a ventilator. It usually resolves though.
Ninja's FIL sounds like cancer, infection or a stroke IMHO. The CT and probably a MRI will hopefully give a diagnosis but it could take a while. If your not getting results consider a teaching hospital. If it IS a 'stroke' they may call it a CVA (cerebrovascular accident) and that can be from a bleed causing pressure on the brain but usually it is a blockage in an artery from a clot or plaque. (Like a heart attack but in the brain.)
I would Google or Wiki some of these terms ahead of time just so your not hearing them for the first time while your also dealing with the shock of a diagnosis. And if it sounds like the Doctor is talking over your head ask him to break that down for you. It's your (his) health and you have a right to understand.