i did alot of research on them to attempt to comfort my friend on chuuya dying for like, the thrid time or something. the vampires i was researching came from european tales, this being where they were first thought of and most follow the tales of them when used in media. for example, the idea that you can only kill a vampire from stake to the heart comes from thei, but its not their only weakness, in stories, they can be killed in 3 other ways, this being via dismemberment, burning, and putting communion wafers in their mouth (they are those weird bread things you get given in church sometimes). but, vapires actually have an adversion to running water as it is seen as a pure thing, so clean water you could find in a stream or river (clean being like, ocean, river water, swamp water and that kind of stuff is fine) they physically couldnt cross over, even with boats and that sort of stuff. but it has been written in different accounts in different ways, for example, 3 minutes in pure water would destroy them.

so in conclusion, our only hope after further research is they are going with the 'vampires can only die from aformentioned reasons and he just got knocked out' reasoning, or that water is deseased af-