Why did Ma keep grandma's death a secret in The Grapes of Wrath?

Ma kept Grandma's death a secret in "The Grapes of Wrath" to protect the family's morale and maintain a sense of hope during their difficult journey. She understood that acknowledging Grandma's passing could demoralize the family and disrupt their already fragile unity. By concealing the truth, Ma aimed to keep the family focused on survival and the promise of a better future in California. This decision underscores her role as a stabilizing force within the family amidst their struggles.