This question is about idiomatic usage of language. The grammatical side of the difference between 寝ろ and 寝てろ is clearly explained here. But I think there is another part of this question: in what situations should one be used over the other? I was recently corrected by a native speaker friend who said 早く寝てろ was incorrect. They said it should be 早く寝ろ. And it prompted me to think if I have been overusing 寝てろ.
Is the use of 早く寝てろ in the two examples shown below idiomatic? Why or why not?
Why does 早く寝てろ sound unnatural in some contexts? And in exactly what situations should we use 早く寝てろ no 早く寝ろ? More generally also: When do we say 寝てろ? When do we say 寝ろ?
Pic 1, source
Pic 2, source