His spiritual condition
Chillingworth suggests that Dimmesdale is suffering because of something that he is not admitting and that something is bothering him (hinting of a relationship between him and Hester.)
I think he seen something like a symbol that has to do with the Scarlet Letter!
Hester suggest that he should goes to England with her and pearl but also confront roger prynne
Chillingworth wastes away and dies within a year of the minister's passing, leaving a sizable inheritance to Pearl.