In the process of therapy, questions are asked about the possible conflicts that may have triggered ALS. When your father verbally expresses his felt sense of emotions of the triggering event, his body will begin to repair and ALS will improve or even be eliminated.
For example I would ask him if he has fallen physically and has derided himself or has been derided by others. If he can recall such an event, I'll ask him to fully express what it felt like?
From there I would explore with your father some other possible factors. Usually when we "hit it" the client KNOWS it and it hits him like a brick.
Sometimes the client may feel shivers, turns red and feels disoriented for a few days. When this happens I know the patient will recover.