Some speculation of this timeline I have?
1. Tsukasa become the sacrifical lad instead of other child and fully become a supernatural
2. Amane's still grown up sick, but manageable. His parent still dies, maybe from supernatural or dying from confusion of remembering having a twin and now only have one?
3. To keep Amane's alive, instead of curing Amane's sickness, Tsukasa wished for time to be dilated within the house and Amane's, while still be able to grow up, slowly acclimated into a supernatural because the time manipulation in his house.
4. Amane's none the wisher about what happened, still feel the lost of his twin and feel miserable even thought he have achieved all his life dream. Because in the main timeline, no matter how much Tsukasa f*ck him up, you can feel that Amane always care for him. He's just confused whether his twin is HIS twin or has been changed to something.
5. I'm still curious on the subplor of young Amane trying to fix the school clock and Tsukasa goating him into it. What's the result of it? Hanako's seems forgotten about it, so it's probably something important that affect main timeline and probably this timeline.