showing no signs of deteriation

My 88 year old dad who has smoked all his life was diagnosed in March 2012 with inoperable lung cancer. His doctor told him he had 3 to 4 months to live. He did not get any treatment nor his he on any medication for the cancer. This is almost 6 months later and he has had no discomfort or any sign of feeling ill. Has anyone out there had the same experience. My dad won't go see another doctor nor will he go for other tests. He says when the time comes the time will come and he is ready.

Hopefull