Complex sentence: Prior to this he was married to Rosalie Elizabeth (Betty) Howell (deceased) and they had three children, a son Roger, born in 1940 and twin daughters, Susan and Gillian born in 1945.
Split into simpler sentences: Prior to this he was married to Rosalie Elizabeth "Betty" nee Howell, now deceased. He has three children from his marriage to Betty, a son Roger, born in 1940 and twin daughters, Susan and Gillian born in 1945.