"Cancer" by Stanley Plumly.
Now to see what wasn’t seen before:
the old loved landscape fading from the window,
the druid soul within the dying tree,
the depth of blue coloring the cornflower,
the birthday-ribbon river of a road,
and the young man who resembles you
opening a door in the half-built house
you helped your father build,
saying, in your voice, come forth.
The full poem is here.