。
Fred's delirium has subsided now and he's sleeping quietly.
Literal
Now [topic-は] Fred [attributive-の] delirium [subject-が] has-subsided-[and-て] quietly is-sleeping-[continuous-ています].
A narrative update on a sick character. 錯乱 ('delirium, confusion, mental disturbance') is a formal/medical term. 治まる ('to subside, to settle, to calm down') — distinct from 治る ('to heal'), 治まる is about disturbance subsiding, whether of illness, storms, pain, or social unrest. 静かに 'quietly' is the adverbial of 静か. ~ている marks the ongoing state.