In the second paragraph we learn that Henry Dashwood had been married before and had a son (John) by that marriage, as well as 3 daughters by his current marriage. Henry's first wife was wealthy, and half her fortune went to John when he came of age (age 21, I believe?). John married (& married well) shortly after that, and he is described as steady & respectable; five paragraphs later, however, we read the following additional description:

He was not an ill-disposed young man, unless to be rather cold hearted, and rather selfish, is to be ill-disposed: but he was, in general, well respected; for he conducted himself with propriety in the discharge of his ordinary duties.

and we read the following about Mrs John Dashwood:

Had he married a more amiable woman, he might have been made still more respectable than he was; he might even have been made amiable himself; for he was very young when he married, and very fond of his wife. But Mrs. John Dashwood was a strong caricature of himself; more narrow-minded and selfish.

Henry Dashwood is cheerful & good-hearted, but his son is selfish & cold-hearted. Does John take after his mother? We don't know anything about the first Mrs Henry Dashwood, except that she married a man who wasn't wealthy -- perhaps she was counting on the Norland inheritance? Or perhaps John was simply spoiled.