How can I prove that Sophocles has or has not sucessfully refued Plato's Objection to Euthyphro's Divine theor

Answer 1

get a large poster board,
divide it into 3 sections, vertically
label the sections, SUPPORTS, PLATO, DOESNT SUPPORT

first, in the middle, write down Plato's objection, dividing it into individual points or concepts
then look at Sophocles, search for each point, was it addressed or not, how well was it addressed/countered, put what you find into the appropriate category, supports, or doesnt
if any objection wasnt addressed at all, it wasnt supported
this will get you started
when you are done, see where most of the evidence lies, which has the strongest points , for or against