Spoilers from novel

 MadelineMaureen:

Can anyone help me. 

Does the novel have a reason why Song Mo's father hates him so much? Even before he joins his uncles army he was being beaten and thrown out of the house regularly. He is the eldest son and heir. All the siblings share the same mother, so I'm genuinely confused as to why his father is so hell bent from the jump to get ride of him. I would understand more if their wasn't abuse prior to him joining the army. 

I can't tell if Han was equally abused as a child, but I know that their father dotes on him. And reading some novel spoilers is a bit of a mini me to the duke. So was it that the father was able to better mold the younger brother, and Song Mo was more willing to fight back and run to his maternal family?  Does it really just come down to Song Mo's father not being able to break and remold him? 

Song Han only shares the same father with Song Mo.  His mother is a mistress which makes him illegitimate and have no ties to the Song family.  Being a illegitimate child is the lowest and worst status anyone could  have.  His mother never married into the Duke/Song Household as a concubine b/c Song YiChun sent her away after she gave birth to him.  Song Han grew up under the impression that he and Song Mo shared same parents until he was around 10 years old.  

Song YiChun is average/not too smart guy.   He is not thorough, proud and arrogant.   Song YiChun's dad (Old Duke) entrusted him with a task in which he failed and was in trouble for.    It  was Madame Jiang's brother who told on him to the Old Duke.  Song YiChun was very furious and felt betrayed and also put the the blame on Madame Jiang.  After that incident, the Old Duke granted Madame Jiang the authority to run the household.  Song Mo is being hated b/c of Song YiChun's relationship with Madame Jiang and that Song Mo is closer to Jiang Meisun.   Song YiChun do not want the title to be inherited by Song Mo b/c he believes Song Mo will benefit the Jiang family more and that he will not have a place in the duke household.  

Song YiChun than thought of a plan in which he would switch out Madame Jiang and Li Niang (mistress)'s babies since they were both pregnant around the same time.  Song YiChun wanted to use this as a way of torture esp when and if Madame Jiang finds out that the baby she doted on is not her baby.  Song Yi Chun wanted the second son, Han to be on his side and make sure he has no familial ties to the Jiang family.      

Song Han was doted and loved by his father, mother and brother.  Song Han didn't know of his real identity until he was around 10 years old.   His mother saw him on the streets when he was on his way to school/lessons.  His mother approached him and told him everything and even show the girl (who resembles a young Madame Jiang) who was switched with him at birth.  Since then, he knew he can't turn his back on his father b/c he will be the only person who will support him.   Song Han also gaves money to the real mom so she doesn't bother him.