Who is Richard Gibson from A Great Deliverance and what is their importance?

Richard Gibson is the nephew of William Teys and the cousin of Roberta and Gillian Teys. Gibson is a large man with a swarthy complexion. He is described as "enormous" and "bull-necked" and stands just over six feet tall (pg. 123.) Gibson has brown eyes and black hair. Richard Gibson is married to Madeline and is having an illicit affair with Stepha Odell. Gibson also admits to having a short-lived sexual relationship with his cousin Gillian. It is Richard Gibson who has Roberta Teys committed to an asylum after Roberta admits killing her father. Gibson's motive for hospitalizing Roberta is never made clear in the narrative. One can assume that it has something to do with Gibson's inheriting Gembler Farm.