Max owed people a lot of money, yet no money was taken from his body. He was sedated instead of poisoned. He mentioned wanting to leave to America. He has a secret passage in his house which Eva went through. Max's body and trunk vanished from the scene.
I believe that Max faked his death. He used the somnus flower to make it appear as if he was dead, and once everyone left the dining room he made his way to get his things and leave through the secret passage.