You stated that he is kind of afraid of going to sleep because of that thick saliva - mucos. Man - I remember those feelings. I was more than "kind of afraid", I was terrified. My RO kept reassuring me that I would wake myself up if I couldn't get a breath. But it made getting sleep even harder and the more tired I got - the more I was upset. A mean circle. But he has had that last radiation - and soon there will be a light at the end of the tunnel which is not a train.