We can't help but feel a little bad for John. On one hand, he's not exactly a good guy; after all, he basically leaves his sisters and stepmother penniless after their father dies. On the other hand, though, he didn't want to do it, and he later feels guilty about it – his wife Fanny pressured him into keeping all of the inheritance money. Of course, his wife's not entirely to blame, since he's just as greedy and smarmy as she is (he practically salivates over the idea of being related to rich and dignified Colonel Brandon).
However, John isn't completely bad at heart; he does seem to have some genuine affection for his sisters, since he's always happy to see them, and in his own way, he wants to make sure they end up OK. He's constantly asking Fanny if Elinor and Marianne can come and visit, or if he can give them little gifts of money to help them out, only to get shot down by his conscience-free, heartless wife. Because John is still a Dashwood, he's not all bad, but because he's under the influence of the Ferrars, he's not all good, either.