High School Girl's Friend (2001)

Genichiro, a lonely retired man living with his son’s family who mostly ignores him, feels closest to his granddaughter who is in highschool. Through her, Genichiro meets another high school girl, Mina, who also feels ignored by her family. She is also troubled by her friend’s pregnancy and the bankruptcy of her father’s company. Unlike her friends, Mina has an ungilded view of life and finds herself comforted by Genichiro’s wisdom. Genichiro likewise is happy to be making a difference in someone’s life.

Unfortunately the movie High School Girl's Friend is not yet available on HBO Max.