1960s Farm System Saves My Sister

The protagonist travels to the 1960s. His biological father is indifferent, and his stepmother treats him with disdain, leaving him bedridden to die. Only his sister offers warmth. He unlocks a farm system. To prevent his sister from being sold, he makes a living for them. He cuts ties with his biological father, sells his mother's work quota, leaves his original family, and starts a new life.