If the model isn't ragdolling upon death then you might have a mod that's breaking the ragdoll, sadly i don't have a quick solution for finding the mod that might be breaking it, the only way I know is to disable all of your mods then enable them one by one(or more) while using this model to see which mod(or mods) are breaking the ragdoll of the model

oh but i have animation addons i cant see the death poses