Once the order was given, the fate of the Jiang family could be foreseen. The men would die "accidentally"on the way to exile, and the women would either be played to death or starve to death in the Education Bureau. Jiang Tian would also become truly alone.
Jiu Xuanji did a good job. He ordered people to tell him the latest news about the Jiang family every day. It was Jiang Tian's choice.
If he could stand by and watch the Jiang Family die, Zhang Ronghua wouldn't want him even if he had to join them. He couldn't use a person who could abandon his own family!
When Emperor Xia found out, he would probably issue an edict immediately, ordering people to cripple Jiang Tian's cultivation before sending him on his way.
Only the dead would not take revenge. He was afraid that Jiang Tian would take the wrong path and blame himself. If that was the case, letting Jiang Tian escape would be a disaster for Great Xia.