My Father Was Just Diagnosed With Squamous Cell Cancer. He

My father was just diagnosed with squamous cell cancer. He has a spot on his neck and a large growth under his armpit. I don't have many details, as this was just passed on by my sister. They are talking chemo, but what are we really looking at? Is this/Could this be life threatening for an 81 yr.old man? He previously had some SCC spots removed from his ear 5-6 yrs. ago.