Did I fall asleep and miss something but I remember the body of the ambassador's husband being found yet at the end she is stating that she found who who was laying flowers at her son's grave? When did he die?
The husband or the son. If it's the latter, you probably haven't watched the entire series and to answer your question would be considered a 'spoiler'. If it's the former, he died when he followed his two sons into the woods near residence.