None of us has experienced loss on the level that Superman has.
As a baby, he lost nearly everything at once—his parents, his home, his planet, his very identity. Like any baby, he did not yet know conscious love, but it's a heartbreaking reminder of the power of the human condition that, years later, he would feel it for people and places he will never remember. And he isn't even human.
What we mortals experience is typically the opposite. Most everything we lose is something—or someone—we first loved, consciously. In practical terms, anything we lose has to be smaller than what Superman lost, yet when it's your turn to grieve, it sure can feel like you lost your planet.
What strength can we take from a fictional character's lifelong struggle? Not much, and truthfully, not much from a real person's struggle, either. No matter how inspirational or comforting we find another's willpower, and no matter how loved and supported we are by others in any time of need, we must all handle the hardest part of loss alone.
I don't know about Kryptonians, but the human heart has four chambers. Yet sometimes it feels like we could use many more than that.