Don't give up hope or give into the statistics of a year. Depending upon your step-father's overall health and determination he could live much longer than they think. My husband has survived 28 months with Stage IV EC adenocarcinoma. Even though he is not doing well now, he got healthy enough to return to work full time, play hockey, softball and eat normally.
My husband went through a lot and there were times we wondered if what they were doing to his body would really make him better but it did. He has never been cancer free since his diagnosis but he was able to have some quality to his life following the initial diagnosis.
I am sorry your step-dad, mom, you and the rest of your family are going to go through this. Best wishes to all of you.