I'm about to make you cry .............
Ok so when hiro and tadashi first got at cass' and hiro was sad because of their parents dying so tadashi would sing 'don't you worry child' because he is a big supportive bro , then when tadashi dies he sings that to himself when he thinks about him .
Then when he has kids and the mother dies he tells his kids about how tadashi would sing that to him and he will sing 'don't you worry child' to his kids .
HAPPY CRYING
