@Kaarme
IIRC, the house he got was falling apart in places and a complete mess in others (and still is. IIRC, the areas we tend to see are the few they use regularly and as such had cleaned up and repaired), the first servant he got was half-blind and increasingly senile (and also chose to go with him, since he pretty much raised the Duke), the second he got was inexperienced and also chose to join him due to being in love with him (and potentially there being bad blood between her mother and the Duke's), meaning he only really has servants because the servants decided to work for him.
The main estate has been trying to pass him over in the line of succession (which is a
major thing in any culture, especially if it deals with a noble title, especially if it's a title as high-ranking as duke, it's a huge insult, and is pretty much disowning him and kicking him out of the family all together).
Disinheriting someone is the sort of thing wars have been fought over.
Honestly, I'm wondering where his father is.
While the story is called the Duke of Death and people refer to him as Duke at times, he's actually just the heir right now. His mother can't do anything to his inheritance without his father getting involved, since it's
his title and
his estates.