Suffering

After all the suffering Harry has gone through after losing everyone he loved, How can he succumb to the pain? He is just one step ahead of just giving up. Can he hold on?
What if there's a path to change all of his sufferings?
Will he remain determined enough to change the future alone? But he vows that he will change the future. Nothing can stop him.
He has to succeed.
But why is that ancient creature helping him?