Is there any chance in which we use "such" as an adverb?
A nice person answered my questions in two short and brief answers.
The following two sentence are for replying. Which should I use?

1. Thanks, especially for such a short and brief answer.
2. Thanks, especially for such short and brief answers.
I'm not sure which one should be used.
Is there any chance in which we use "such" as an adverb?

Question

Is there any chance in which we use "such" as an adverb?
A nice person answered my questions in two short and brief answers.
The following two sentence are for replying.  Which should I use?

1. Thanks, especially for such a short and brief answer. 
2. Thanks, especially for such short and brief answers.
I'm not sure which one should be used.
Is there any chance in which we use "such" as an adverb?

Answer

If you received one answer, you'd use the first; if you received two or more answers, you'd use the second.  Your use of 'such' is fine in both options.

What confuses me is why you want to say 'short and brief'.  These two adjectives have the same meaning - "short" means "not long" and "brief" means .... well, "not long".   Both could potentially even be seen as negative : after all, wouldn't you have preferred a fuller answer? I'm wondering if the word you actually want is "concise". This means that they gave you a short but comprehensive reply, answering your question fully and clearly in relatively few words.

Answer

Thanks, Chirs. I had found this webpage which cleared up my doubts.
https://dictionary.cambridge.org/zht/%E8%AA%9E%E6%B3%95/%E8%8B%B1%E5%BC%8F%E8%AA%9E%E6%B3%95/such-or-so

Answer

Su.ki answered your question well.  Since you asked about "such", it might be useful to distinguish between "such" and "so".

so [adj]
such [article adj noun]

The dog was so cute that I kissed it.
It was such a cute dog that I kissed it.