As someone who endured chemo and lived, that was a tough read... RIP.
Compassion is the awareness of a deep bond between yourself and all creatures. But there are two sides to compassion, two sides to this bond. On the one hand, since you are still here as a physical body, you share the vulnerability and mortality of your physical form with every other human and with every living being. Next time you say "I have nothing in common with this person," remember that you have a great deal in common: A few years from now -- two years or seventy years, it doesn't make much difference-- both of you will have become rotting corpses, then piles of dust, then nothing at all. This is a sobering and humbling realization that leaves little room for pride. Is this a negative thought? No, it is a fact. Why close your eyes to it? In that sense, there is total equality between you and every other creature.
One of the most powerful spiritual practices is to meditate deeply on the mortality of physical forms, including your own. This is called: Die before you die. Go into it deeply. Your physical form is dissolving, is no more. Then a moment comes when all mind-forms or thoughts also dies. Yet you are still there-- the divine presence that you are. Radiant, fully awake. Nothing that was real ever died, only names, forms, and illusions.
The realizaton of this deathless dimension, your true nature, is the other side of compassion. On a deep feeling-level, you now recognize not only your own immortality but through your own that of every other creature as well. On the level of form, you share mortality and the precariousness of existence. On the level of Being, you share eternal, radiant life. These are the two aspects of compassion. In compassion, the seemingly opposite feelings of sadness and joy merge into one and become transmuted into a deep inner peace. This is the peace of God. It is one of the most noble feelings that humans are capable of, and it has great healing and transformative power. But true compassion, as I have just described it, is as yet rare. To have deep empathy for the suffering of another being certainly requires a high degree of consciousness but represents only one side of compassion. It is not complete. True compassion goes beyond empathy or sympathy. It does not happen until sadness merges with joy, the joy of Being beyond form, the joy of eternal life.