流すのもなんなので - Translation help

Question

I'm currently reading through the 灰と幻想のグリムガル light novel at the moment and have become stuck on this page containing the below sentence.

I've provided an image for context as I think you'll need it.

The first half of the sentence I need help with is this:

流すのもなんなので、ハルヒロはとりあえず「....親族なの？」と尋ねてみた。

The official English Translation for this book translates it as so:

It would be awkward to leave that hanging, so Haruhiro offered, “...Maybe they're in the same family?”.

I know it's connected to the topic of the last paragraph, but I can't seem to fully wrap my head around its full meaning and how its deconstructed.

If someone could explain this to me like I'm 5 that would be fantastic.

Thanks,

Archie ♥

Answer 1

In that context,

「流{なが}す」 means 「聞{き}き流す」, which means "to take no notice and show no reaction" to what has just been said by the other person. People tend to 「流す」 what they think to be poor jokes, uninteresting or useless comments, etc.　　

「なん」 here is a filler word for an actual word that is negative in meaning. In this case, that word would be 「良{よ}くない」, 「悪{わる}い」, etc.

So, 「流すのもなんなので」 would mean something along the lines of:

"As it would not be too cool to take no notice of (what Yume has just said)"