Hakamori Tsuma to Kogane Ryuu - Hamerareta Hanayomedesuga, Gosenzo-sama ga Tasukete Kureru youdesu

I was lucky to marry the mysterious head of the Vernois Dukedom, but he is 80 years old, bedridden, unconscious, and cursed. It was clearly a political marriage, but my 66-year-old brother-in-law, who is acting as the head of the family, told me to "be the gravekeeper on my own." I was fed up with being treated like a servant, but my ancestor enshrined in the mausoleum was a golden dragon that produces gold mines. "I'll help you out of all the terrible things you've been through!" the golden dragon said arrogantly, but...