Why was njoroge's joy had faded?

The strike brings together conflicting elements including Njoroge's father. During the arguing of the strike, the father attacks Jacobo who is a rich African. The father loses his job as a caretaker of some of his native land, the family has to move, and the brothers, who continue to fund Njoroge's education, lose respect for their father. The joy is gone because the family's entire life has changed.