I think it is depicting a Burman, though by whom it was drawn is another question. The length of the handle and shape of the pommel do suggest Thai (specifically, Rattanakosin Period), but the lacquered or dark wood scabbard with metal bands suggests more a Tai Shan style. Maybe the guy just happened to be holding a Thai daab he picked up after a battle?
The sword is fairly simplified and a bit stylized, so I think, overall, it is supposed to be a Burman and the sword handle is just artistic interpretation.
Here is my miniature (marionette) version of the same guy:
