Rain is the way the speaker lets grief show without having to admit it. Each time they miss their father, the weather seems to match, and the rain becomes a kind of cover, a way to hide their pain from the world. It's a quiet, private idea: the sky does the crying so the speaker doesn't have to.
The middle stanza turns to a memory. The father used to pat the speaker's back and say they had done okay, even after a failure. That small gesture says a lot about what he gave them: comfort without judgment. The final stanza admits that life has become hard, and the speaker wants to "come back," which suggests a longing for the safety of that time, or perhaps for him. Other people have come and gone, but none compare. The mood is tender, lonely, and a little worn down, and the repeated trailing dots make it feel like the speaker's voice keeps fading into silence.