Why did stantey lie to his mother in the letter?

Stanley lied to his mother in the letter to protect her from the harsh realities of his life at Camp Green Lake. He wanted to spare her from worrying about his situation and the injustices he faced there. By crafting a more positive narrative, he aimed to maintain her trust and keep her spirits high, even as he dealt with his own struggles. This choice reflects his desire to shield his family from pain and disappointment.