His face was too pale, making him look dead. He almost was. He would be, if Heimdall hadn't spotted him in time.

Thor would never be able to forgive himself for not noticing the dullness in Loki's eyes, or how he only got skinnier and skinnier. He would never forgive himself for not realizing that something was wrong when Loki suddenly stopped with everything he ever found interesting, except his pranks, and instead hid in his chambers all day, not bothering to leave it even for dinner.

"I'm not hungry brother."

They all should have noticed it. And they definately should have known that there was something wrong with him when the All-father cast him out to midgard as a punishment for putting poison in the horses water, and he didn't even protest. He only smiled in a way that he always smiled when he knew something that the others didn't.

"I, Odin Allfather, cast you out."

It didn't even pass a week before Heimdall left his post in a hurry, running to get the king. (Heimdall never left his post, and just that was a warning enough that something was terribly wrong.)

"He's going to end his life."

When Loki finally was back in Asgard he had lost a large amount of blood, his wrists looking completely gruesome. Thor had seen death, he had caused death but seeing death in his brother was something he never, ever would be prepared for. And something he never, ever would want to see again.

"We need to stop the bleeding."

It seemed simple at first, but Thor should've known. Loki was never simple.

"There is poison in his veins. A poison we can't recognize. There is a risk of that he'll never be awaken again."

No, Thor would never forgive himself for not being able to save his brother in time. And he would never forgive his father for giving Loki what he wanted, a way to take his life.
And even if Eir managed to save him, his mind would be just as broken as his mortal body.

The sobs wrecked his body, and the rain began to fall once again.