I have no clue on that. The H cocoons come from Brazil, then the silk fabric is woven in Lyon. Your guess is as good as mine
But, if you think of all the silks that H makes: vintage - woven differently , twill, summer twill - lightweight, wash - basic twill but acid washed ?, they all feel different, you can get the feel you want by weaving (vintage) or processing (acid wash) or changing the weight (summer twill) ...
And if you look on the caretag - they all say 100 % silk, as if they were all made the same , which they are not
So I bet you could get almost any feel with ethical silk, IF you tried hard enough
Fakes often dont feel right because they are lighter weight silk, but there are fakes of the correct weight and I cant tell them apart based on the hand of the silk.
The fakers chose to use lighter weight silk, for the most part, because of cost, they are aiming for a $30 price point not a $400 price point. They can do EXACT copies but they would sell fewer
PS I dont know if H would claim their silk is ethical or not
Remember the kerfuffle about crocodile skins for Birkins? Jane Birkin announced she would no longer allow them to use her name because their leather was not humanely produced. LOTS of stuff in the press about that ... the matter was quietly settled - not much press coverage ... I dont know if todays croco is more ethical or not .... well they still sell croco Birkins ...