why did jeanne think that papas drinking was caused by his isolation after his arrival to manzanar

Jeanne notices the change in her father when she is only eleven-years old. Although she thinks that Manzanar has made her stronger, she feels that her papa is drowning in isolation. Papa feels his life has amounted to nothing. Papa must rely on Mama and Woody because he refuses to take a menial job. He slowly drinks himself to death causing him to be even more isolated from the world and his family.

Papa’s life ended at Manzanar.… Until this trip I had not been able to admit that my own life really began there.