Taka left home when he was a teenager, around that time his parents were divorced too. He left to live with his grandma until he can buy his own place. He made this song for his parents (they are both famous singers in japan). And they were at that exact concert, in the audience. That's the reason why he got so emotional and started crying. He wanted to be a singer like his parents but both of them were against it (they knew how hard it was to be successful). Afterwards he experienced a lot of prejudice because everyone thought his talent came from his parents and not him so he changed his name. The song is his way of apologizing to his parents