Kodomo No Jikan Temporada 1 Episódio 6

A flash back is told of Reijis parents and Rins mother. Reijis father was an alcoholic and got angry over minor things; one night his parents got in a car crash and died. Afterwards, Reiji moved in with his cousin Aki, Rins mother, whom had lung cancer, but did not tell any one until it was too late.