Wearing silver and turquoise rings, a silver belt buckle and a pistol at his side, the man is very wealthy and doesn't take no for an answer. He owns a large ranch and is one of the major brahmin barons in the republic.
Politically, he supports president Tandi's option of peacefully expanding the NCR and tries to keep less than stellar activities of the Republic at a manageable minimum. He had reservations about entering into an alliance with the Bishop family of New Reno, which makes him a threat in John Bishop's eyes. Unsurprisingly, he is marked for termination by him.
Westin can be found on his ranch in NCR. To get past the guard and forcefield you will need a reference, speak with the Sheriff of NCR and ask for some "honest work". Once on the ranch you can accept a quest to help Westin stop raids on his brahmin.