[color=red]1-Stupid that he is, he told everything to me.
[color=indigo]2-Stupid as he is, he told everything to me.
Which of the above corresponds to which of the below:
[color=darkred]a-Because he is stupid, he told everything to me.
[color=darkblue]b-Although he is stupid, he told everything to me.
Gratefully,
Navi.