I think even telling her the truth wouldn’t have helped. She’s known his family is being hunted and targeted…
Nah! I doubt that he’s fond of her or him. He just feels guilty and indebted to their family that’s all.
Remember how he was described. He betrayed their father, and just feels envious, guilty and I would say the only positive thing he feels or have for them is respect.
If he had uncle fond air, he would have used a decoy that looks like the sister and is not actually the sister.
Not telling his sister the truth left her vulnerable. She couldn’t protect herself and be cautious about someone misleading her.
On the other side he at least gave her a normal upbringing but his enemies are arrogant and ruthless. They left him with no hope, now he’s gonna be very dangerous and unstoppable, as he has no attachment.
1 
Remember how he was described. He betrayed their father, and just feels envious, guilty and I would say the only positive thing he feels or have for them is respect.
If he had uncle fond air, he would have used a decoy that looks like the sister and is not actually the sister.
On the other side he at least gave her a normal upbringing but his enemies are arrogant and ruthless. They left him with no hope, now he’s gonna be very dangerous and unstoppable, as he has no attachment.
It’s a Pyrrhic victory for the opponents.
Also, how does general Gu Yu ride a horse? How crippled is he?
I also can’t believe they approved so many writers for that story, that alone was insane.