Mr. Casaubon doesn't have a second attack, so everyone thinks he's on the mend.
Lydgate knows better, though, and warns Casaubon to take it easy – relax, no hard studying, etc.
Casaubon's not happy about this. He's too serious to play cards or anything in the evening, and he'd rather read Greek manuscripts than a novel.
He doesn't know how to relax and have fun.
In private, Dorothea asks Lydgate what the real story is.
Lydgate takes her seriously enough to give her the real scoop: Casaubon shouldn't be agitated for any reason, or he might have another, more serious, heart attack. And she should try to keep him from working too hard.
Dorothea knows how hard that will be.
Meanwhile, though, someone needs to write to Will to tell him that Casaubon's bad health will prevent him from having any visitors.
Dorothea asks her uncle, Mr. Brooke, to write to him.
Mr. Brooke has his own scatter-brained ideas, though, and decides later to invite Will to his own house for a visit (kind of weird since they only met once, and briefly, at Lowick).
He doesn't tell either Dorothea or Casaubon that Will Ladislaw will be visiting at Tipton Grange.