Grief (n.) was not caused in Achilles by Patroclus' death — not everyone mourns a comrade that way — but by his own decision that it was fitting to grieve.
Grief (n.) must be ended at any cost only when it is your own; another's grief you ease as far as you can, since only your own is in your power.
Grief (n.) is often the bill for reckoning on the uncertain: you counted on your friend to outlive you; blame yourself, not fate.
Grief (n.) of another is no concern of mine; my own grief is — so I end mine at all costs, and try to check his, but not at all costs.
Grief (n.) came to Achilles not from Patroclus' death, but because he wanted to grieve.
Grief (n.) may groan — only do not groan in the centre of your being.
Grief (n.) for a son or friend no longer granted to you is longing for a fig in winter.
Grief (n.) should not be caught: moan alongside a grieving woman if it helps, but never inwardly, any more than you would take poison to help a poisoned friend.