Maybe the unfairness started when the person was doing well. The subsequent fall from grace is, in truth, fairness in disguise.
When other people gain an advantage over you, the sense of unfairness is often jealousy in disguise. You strive to restore the "balance". But when you gain an advantage over others, it's called "success" which you use to define happiness. You don't think about restoring the balance.
There are more things to learn in life when you are swimming against the current. That, in itself, is the fairest thing in life. The life lesson you learned cannot be taken away from you, unlike a job, a gf or value of your material possession. It's just that most people do not attach a meaningful value to non-material things.
Peace is the prize that you should be seeking at all times, not a consolation after you have fallen behind others.