Pytosis. Have Weakness Of Extremities, Melanoma Lesion Removed, Myasthenia Gravis. Had A PET Scan. Treatment?

My father presented with extreme weakness of the extremities, pytosis, difficulty swallowing in August, 2012. He had a >.1mm melanoma lesion removed in October, 2012. He was to have a SLN however the sentinel node was in his chest and could not be obtained. By January, 2013 he was dx with myasthenia gravis. He began a treatment of mestinon and a 6 week treatment of prednisone. These treatments alleviated the MG symptoms. However, in early March he had a PET scan that showed numerous PEs. He was hospitalized and put on Lovenox. He had a DVT in his calf. The PET scan also showed suspicious spots on both lungs. He had a biopsy of his right lung yesterday. What are the chances that it is sclc or nsclc as opposed to "scarring" or non-malignancy? Given the symptoms presented where might he fall in the ranking? Early or extensive? I might add the PET scan didn't show any other locations that might be affected He also told me he had the melanoma lesion for "years" before it was excised. How treatable is his condition if we have caught it early? Thank you.