¡Auxilio!
I have finished the majority of my workbook on the subjunctive, and I feel like I am far from the more thorough understanding I had hoped I would have....

I'm going to need to find more exercises on this.......
Anyway, the final chapter of the book consists entirely of exercises that mix up use of subjunctive, indicative, and infinitive ... present and past tenses ... and noun, adjective, adverb and hypothetical uses of the subjunctive. Again, I feel quite unprepared to master these exercises.
Here are my questions from the first set of problems (fill in the blank with a verb that is given):
6) Su mamá le dijo que se durmiera ya que era tarde.
My question: I don't even understand what this sentence means. I can't even come close to figuring it out. I know every word, but I come up with something like: "his mother told him that he slept already was late", which I am 100% positive is not even close to the true meaning...............
8) ¿No había vuelos que fueran a Tierra del Fuego en aquella época?
My question: Again, I don't really understand this ... (although it makes a LITTLE more sense to me than #6) ... the meaning I would come up with is something like: "Weren't there any flights to Tierra del Fuego in that time?" Grammatically, it makes sense to me ... but I don't really think that I have it right.......
15) El dependiente de la tienda salió después de que su jefe contara el dinero.
My question: I don't understand why the subjunctive is used here. I thought the underlined verb should be "contó", in the indicative. The shop assistant DID leave the shop, after the boss DID count the money. What is the reason for the subjunctive here?
16) No lo dejaría volver a casa a menos que dijera toda la historia escandalosa.
My question: Again, I don't understand the meaning of the sentence. My understanding would be something like: "He would not allow himself to return home unless he told the whole scandalous story." But that doesn't really make sense to me.....
17) Tenía un caballo que miraba mal de un ojo.
My question: AGAIN, I don't understand the meaning of this sentence. Is it something like: "He had a horse that couldn't see out of one eye."???? But doesn't "mirar" mean "to look", not "to see"????
25) Chicos, tan pronto como se pongan los zapatos, podremos salir.
My question: I thought the underlined verb should have been "se hayan puesto". Is that also correct? If not, why not?
Thank you SO MUCH for any help you can give me with these tantas preguntas!!!!