My father is experiencing extreme weakness, difficulty swallowing, eyelids not staying open along with difficulty to breath due to closing sinuses. He gets weaker every day because he isn t eating or getting much sleep. Sounds like something neurological possibly? Once he gets up and walks on the treadmill for a few minutes he seems to get a burst of energy and feels better except that his legs give out so he has to sit down. Once he sits down again everything begins to shut down again? I am at a loss as to what this may be? Any info would be much appreciated. Thank You.
Your fathers complain seem to be due to neuromuscular junction abnormalities likely Lambert Eaton syn Chat Doctor.  It may be myasthenia graves if weakness increases on exertion and decoration with day progression. Another possibility may be some paraneoplastic involvement. I will advise you to consult a neurologist urgently to get proper evaluation and diagnosis. God bless your father, and he may be healthy again.