Bending or unbending your arm is mostly a bicep and tricep muscle action. It’s just a question if she’s able to bend her fingers.
She’s probably going to get that amputated.
I don’t know how old the photo is, but at the rate of deterioration of her forearm, she won’t need to worry about amputation.....it’ll fall off by itself.
In seriousness, that looks too far gone to save (in my non-medical opinion). I would imagine by now, that arm is in the biohazard bin.