I would like to know what "the morning when the darkness would be gone" means in the following sentences:
That night I lay awake in bed, the other guys fast asleep around me, the moon pouring in through the half-open curtain. Sharp memories knocked on the door of my consciousness, and what came to me was an old nightmare, one I had often dreamt as a child, one that had descended upon me with cruel frequency before and after Beniek’s departure.
In it I stood in an endless overgrown field. Everything was still, as if petrified, and an overbearing silence reigned. There was no one – not just near me or within earshot, but anywhere. With the inexplicable logic of dreams, I was certain that I was alone in this world, the last member of a forsaken race. I looked around and started to see rectangular stones reaching out of the grass. They were blank and smooth, and I knew they were tombstones. They were watching me. Their stillness made my heart race with panic; standing there was like an infinite fall. It all seemed so undeniably real, not like a dream but a premonition. I’d feel violated upon waking. Outside, in the darkness of the night, the branch of a chestnut tree would sway in the wind and scratch against my window like a monster demanding admission, and without thinking I’d get out of bed and tiptoe across the cool wooden floor to my mother’s room. We would sleep together, her enveloping me from behind with her arms around my tummy, her stale warm breath above my head, us breathing in unison, small and large, breathing in and out until the morning when the darkness would be gone and Granny would come to stir us, scolding us as we rubbed clusters of sleep from the corners of our eyes.
In this novel which is set in the 1980's in Poland under the socialist regime, where homosexuality was socially unacceptable, the protagonist Ludwik (a university graduate) left Poland in 1981 to live in the United States of America. And he remembers what it was like back then in Poland, where he went to the agricultural camp (which was mandatory for college graduation). At the camp, he lay in his bed at night and slept, which was when his familiar nightmare visited him.
In this part, I wonder whether this "morning" here would mean proper (?) morning, like at 8 or 9 a.m., or it would have a meaning close to "dawn," "near sunrise." I came to be confused because of the expression "the darkness would be gone" which is in the "when" clause that modifies the "morning." So I thought, the darkness could be gone at a pretty early hour, even at 5 a.m. in summertime... But then I came to wonder whether "when" here is similar to "after," meaning "the morning after the darkness would be gone."
I am an English learner from South Korea, so thank you for your patience in advance as I may not know obvious things. I would very much appreciate your help. :)