This is the only picture I have of the inside of the hood ... the way it is attached inside is what
Psab keel mentioned a so-called 'blind' hem-stitch :
View attachment 1682003
For a long time I believed there were 3 or even 4 layers, so 2 pieces of fabric 1) the rest of the hood, with 6 inches extra fabric, folded at the front and going inwards and 2) the facing (extra 12 inches) just folded in half (6 inches) and stitched together at the front with 1) ... then going inside about 6 inches ... but looking at the inside the facing doesn't look to be double layered in thickness ... what do you think?
Chaïm