“…physical ailments, no matter how severe, cannot bring any change in the inherent condition of the soul…”

Regarding your questions concerning the condition of the soul during illness. The passages in the "Gleanings" make it quite clear that physical ailments, no matter how severe, cannot bring any change in the inherent condition of the soul, As Baha'u'llah says: 'The spirit is permanent and steadfast in its station'. The veil or hindrance that interposes between soul and body during physical disease is sickness itself. Sickness reveals a lack of balance in human organism, an absence of equilibrium in the forces essential for the normal functioning of the human body. 
(From a letter written on behalf of Shoghi Effendi to an individual believer, March 8, 1936; compilation: ‘Lights of Guidance’)