Search:

To me, this sounds akward :(

Он был не в духе normally refers to a particular event in the past whereas the expression 'he had a bad attitude' means something more specific.

You can find whatever you want in Yandex. The sentences you wrote seem to be rather bookish. I mean that they're all fine but there's something that make you think they're bookish. I think it's the...

Yeah, of course, you can translate it like that! I'm sure there are tons of ways of saying 'he had a bad attitude' in Russian. But remembering them may take some time.

The most imortant is that the original sentence should be correct.
At least, it's not as rare as восьмеро!

I think you can say гневный. It's just probably my preference for the word сердитый.
If you mean that he was in no mood to do anything you can say - у него была апатия ко всему. Maybe, someone else...

First of all, I'll fix it:
Он всегда кажется таким сердитым с серьёзным выражением лица. У него было плохое отношение к .... .
I think that you should say what he had a bad attitude towards.
...