This dialogue is from a series called “A discovery of witches”.
The male protagonist, a vampire, is talking to her mom about the sleeping arrangements for his girlfriend, a witch, who is being pursued by dangerous people but has found safety in his boyfriend castle (of course he has a castle). Witches and vampires have never gotten along with each other, so his mother has a little bit of resentment towards this woman but she’s trying not to show it, for the sake of her son.
She needs some rest, it’s been a long journey. I’ll make up her room.
And his son replies:
No, I’ll do it. She’ll be sleeping in my tower.
Now, why does the vampire use the future continuous? Why not the future simple? Would it have a different meaning? Are they interchangeable? If so, why use one over the other?