Question

Why does his mother insist on an open casket funeral for Emmett till

Answer 1

Because she wants everyone to see him for a last time and she wanted to make sure that the people who did that to him know what they have done and accept responsibility for their actions

Answer 2

Mammie (his mother) wanted to show the world what had been done to her son, just because of a misunderstanding and white supremacy. More than 50,000 people showed up at the funeral, and every other person had to be escorted outside because of the horrific sight.