They beat Loki's father until the man became an unrecognizable pile of flesh. During the process, the man screamed in pain for a while. Then he became silent because his throat had torn from all the screaming.
Finally, it got to a point that the man couldn't scream even if his lungs were intact because his ribs had broken and punctured his lungs, so his lungs began to leak.
His father died soon after this point in the punishment. They made sure that Loki heard about it, but he still refused to return.
So the Rein Family moved on to his mother. They let many men rape her in public. When several men had taken too many turns on her and she became unusable, they let animals take their turns too.
All of these still failed to convince Loki to return. He turned a deaf ear to all the stories and jests that he heard about his mother. This forced the Rein Family to up the ante.
