Does Anyone Know This Game? Deer Avenger 4.

Unfortunately, the model got imported without T posing, but a combination of run/attack animation frame.
Also many vertices are not merged.

I don't know much about blender, but I'm still curious if I can fix the model and if it's possible to make good skeleton rig for non T pose model.

I also wonder if it will be possible to also port this model into Garry's Mod.

If there's any suggestion which will help in making this model usable, please tell me.