The speaker is trying to talk to someone from the past, and the opening question, "can i even begin," shows how hard that is. So much time has passed that it feels "behind blue line," as if a boundary separates then from now. The poem reads like a halting letter or a thought spoken aloud, full of slashes, pauses and trailing dots.
Small pieces of news drift in. The speaker now carries a symbol of life and the sea, "blue green / mother of pearl." A grandmother still talks about the person being addressed, and a grandfather has died, "lying in quiet pine box." Postcards arrive from Mexico with no addresses, and the speaker admits to being surprised while the mother was happy. The poem suggests this person may be absent or hard to reach, though it never says so outright.
The feeling is tender but uncertain. The last line, "better than nothing," sums up the mood: a little contact is a small comfort, and it still leaves something unresolved.