(son sued mother both personally and in mother’s capacity as trustee of two trusts in which she disinherited son pursuant to will and trust; while actions pending, mother died and son’s siblings substituted as defendants; son claimed that mother breached joint, mutual and contractual will made with his father entered into 15 years before execution of documents disinheriting him; trial court ruled against son and case affirmed on appeal on basis that irrevocable trust executed seven years after joint and contractual will which revoked or modified join and contractual will; on further review by state Supreme Court, Court determined that joint and contractual will not fully revoked and son could still possibly establish breach of contract as to provisions not revoked; case remanded).