Context: After entering the room and looking at the corpse of her mother's love affair, the girl said these two lines:
あのまま彼がママに会ってたらママを取られてた?
だったら彼は死んだほうがいいってわけ
My literal understanding of the first sentence is "if he and mom met each other, she would be taken away from us/she would leave us", and for the second one is "if that's the case, then it'd be better for him to die". But when I checked the official English translation, I see this
If he hadn't met mom, she would have left us. So isn't it a good thing that he's dying?
あのまま might indicate a situation happened in the past, so if clause type 3 makes sense to me, but shouldn't it be "had met" instead of "hadn't met"? Why does the publisher translate あのまま彼がママに会 as a negative sentence here?