Even though Sir Charles never appears directly in The Hound of the Baskervilles, we owe the guy the respect of mentioning him here since his death is the reason for the story. Actually, over the course of Watson and Holmes' investigations, we do learn a couple of details about him that might be worth noting.
First of all, he's fantastically wealthy. In fact, it's Sir Charles' wealth that makes him a target for Stapleton in the first place. Second, we know that he's the good kind of Baskerville. His younger brother Rodger disappears into South America after developing a bad reputation in England, but Sir Charles gets to stick around and enjoy his social position as a well-respected baronet in Dartmoor.
Doctor Mortimer mentions that, "All of the good work which has been done by Sir Charles will crash to the ground" (3.74) if Sir Henry doesn't come to continue it. This suggests that Sir Charles took his responsibilities to the community pretty seriously, an impression that Laura Lyons only confirms when she mentions that Sir Charles supported her financially after her husband abandoned her and her father refused to help her. It's important that Conan Doyle wants us to like Sir Charles, or at least, to approve of him morally, since his value as a person increases our interest in finding his killer.
We also have a lot of sympathy for Sir Charles for one more reason: he was clearly not a happy camper. We know what it's like to be scared of ghosts—we watch a lot of horror movies here at Shmoop—but we have nothing on Sir Charles'. Doctor Mortimer reports that, "Sir Charles's nervous system was strained to breaking point" (2.41) by his fear of the devil hound that supposedly haunted his family line. Considering the fact that he died with such an expression of fear on his face that Doctor Mortimer almost didn't recognize him, his death must have been absolutely terrifying. He was faced in real-life with a glow-in-the-dark dog out of his worst nightmares. And his weak heart gave out as a result. How can we not feel sorry for the poor guy?