Unfortunately I can’t help you much with identifying the hair type (hopefully someone else out there can!), but since it’s already pretty fried already I think what I would do in your situation is test how it responds to a straightener. You can use a very small strand from the back of the head where it won’t be visible in case it goes badly. Make sure the hair is damp and well-coated with conditioner or some other heat protectant. Worst case scenario is that there isn’t much to be done for her and you’ll have to either live with the frizz or give her a reroot. Good luck!

I wonder if maybe letting her hair sit overnight slathered in conditioner might help with the frizzy ends?
Some people have also had great luck with leaving hair in fabric softener, but I prefer to use conditioner myself, it being made for human hair and all.
It might be worth a try, and then you can always test one or two strands with a hair straightener on the lowest setting. Good luck, she’s very pretty! 🥰

This type of damage unfortunately requires heat to fix… have you done anything with boiling water yet? I haven’t tried on my giochi dolls… yet…
I /think/ it’s acetate or early crappy nylon… Leaning towards nylon since poly wasn’t widely used at this point to my knowledge and nylon was pretty terrible originally