"Write a set of instructions for an alien who has just arrived on earth on how to fix a broken heart. Lay out how to do this in the simplest words. How would you describe it? What would you advise them to do?"
Hullo and welcome,
We are strange creatures, here on this planet. We form deep emotional attachments to all types of creatures and objects. What I mean by emotional attachment is this: I can reach out with my hand and grasp the shoulder (or arm, or hand) of another human standing beside me, and never let go. Then it would be as if we two were physically attached to each other. Humans do this all the time, but we imagine we are doing it with our minds. And we do it not only with other humans but with animals, with objects, with places, and even with ideas. Doing this can sometimes make us feel as though that other human, or thing, is a part of our own body. We call this love. And if what we love goes away or disappears, then we can feel pain in much the same way we would feel pain if we were to lose a part of our physical body. We call this heart-break, and this can be confusing, because it is little to do with the organ in our chest that we call our heart. You will find we often claim the heart has more power than it actually does. There are other words that mean much the same thing as heart-break, like grief.
There is no way to fix this. All you can do is try to make the human with heart-break comfortable. Sometimes it helps to give them an occupation - an activity for their body or their mind that will take their energy and thoughts away from what they have lost. Occasionally it may help to give them another thing to love, but this works less often when what they have lost is another human. Usually it helps just to sit with them, and let them talk about what they have lost. They may cry, which means they may make noises they cannot control and salty water will come out of their eyes. This is not a reason to be alarmed - it is one of our human ways of expressing ourselves, like smiling, or laughing, which you will also encounter.
Heart-break will only heal with time. If you have made your human as comfortable as possible - made sure they have occupations, listened to them them cry - then you have done all you can do. Return to them after the earth has made one full passage around the sun and you may see a change. Return after two passages and the change may be even more pronounced. There is no universal law about how long it takes for a human to heal from heart-break. They will never go back to being exactly the same human as before, but that change is normal. That is one of the ways that humans' minds grow and expand.