The Will for Mahlon H. West has a record in "Heirs and Legatees of Harford County, Maryland 1802-1846" by Henry C. Peden, Jr. 1988, pp. 48. This references states that the Mahlon H. West that married Mary Trego died in 1840. His wife survived him. He had children as follows: William S. West, son; Jesse H. West, son; Rebecca T. Roman, daughter; Elizabeth H. West, daughter; Mary S. West, daughter; Granville T. West, son; and Edward W. West, son.
The Mahlon West that died in the prison in Andersonville, GA in 1863 is probably not the same Mahlon West.