Another comment about Nat, his Mum and her illness; these days, when we are ill, we expect to know and understand what we are suffering from and to have a reasonable chance of being cured. In Nat's day, there was little effective medicine, diagnosis was uncertain and people died suddenly from causes they didn't understand. Probably Nat and his mother had no idea whether she was chronically long term ill or terminally ill, and lots of people were probably off-colour a lot of the time and I imagine people just lived more in the present.
As someone said earlier on the thread, in some ways we are still so similar now and in others we are so different that it is difficult for us to understand. Also Nat was keeping a diary for his own reasons, but I'm sure he didn't anticipate complete strangers would be reading it 150 years in the future!