The speaker addresses Reijo, someone who appears to have died, and warns him that what follows will take "months, not days" of what he calls "intensive care." The phrase borrows from hospital language, but here the care is emotional work: going back over what passed between them, and what the speaker can now see in their years of talking. Reijo's tears were "darkness under your eyes," while the speaker's fears stayed private, "in my head."
The second part turns to a sudden, shocking event. "Black ice" and "skirmish" suggest an accident, though the poem never says so outright. Reijo seems to have acted out the very catastrophe the speaker feared, which makes the loss feel both unexpected and long expected. The closing lines are quietly painful: the speaker came late into Reijo's life and may now be the last to arrive at his death. The mood is grief held in check, plain-spoken and tender, with a little dark wit.