Fiebertraum literally translates to "fever dream". It's a compound noun that vividly describes a dream experienced during a fever, often characterized by its intensity, strangeness, or disorientation.
In the song, the phrase "Der Heimweg ist ein Fiebertraum" (The way home is a fever dream) sets a powerful and somewhat surreal tone. It suggests that the journey back, perhaps after a long and arduous adventure, feels disorienting and unreal, blurring the lines between reality and a dreamlike state. This word is evocative and less common than everyday terms, making it memorable.
"Ein Leben Lang" is a song about coming home from a journey alone, and about carrying someone with you after they are gone.
It opens on the return trip, which the singer calls a fever dream. He asks how they ever crossed the northern sea, how they ever made it over the ice. They reached what they set out for and the dream came true, but the price was high. That last line, "Doch teuer bezahlt", is the hinge the whole song turns on.
Then he is standing where the journey began, thinking back. They set out full of confidence and suspected nothing at all. He can still picture the two of them, eyes forward, sure that nothing could stand up to their dreams. Out into the world, and back again some day. Now he is here without the person he set out with.
The chorus is the promise he makes in answer to that. You are always with me, a whole life long, at my side from the very beginning. Bound together for eternity, together until the last day, for all time. It is spoken to someone who cannot answer, which is what gives it its weight.
The last verses turn it into something he chooses to keep doing. He hopes the other person knows, and he wants them to be certain of one thing: he will never fully leave them behind, because wherever he goes, they come along. When the longing hits, he holds on to the thought that some day they will see each other again. Until he can follow, he carries them with him, a life long.
Santiano build the song out of sea imagery, so grief here sounds like a voyage: a crossing survived, a harbour reached, and one crewmate who did not come back.