I found a little on Henry but you may already have this information:
Social Security Administration Death Index Henry Gerhardt born 19 July 1883 Died May 1971 Last address on file was Waynesville, North Carolina Social Security number issued in Alabama before 1956
The social security number applications are available from the SS Administration.I'm sure others have posted the specifics on how to obtain this record, but it would give the birthdate and probably birthplace and names of parents of the applicant.
Try the North Carolina health department for Henry's death certificate as it would be on file there.
The 1930 Census of Mobile County, AL gives the following family living at 1206 Elmira Street in Mobile:
Henry Gerhardt, age 46, first married at age 34,born in Czechoslovakia, German is native language, speaks English, manager of a loan company Mitzie -, wife, 34, first married at age 22, Czech., German is native language, speaks English Leoncio -, son, 10, Czech., language German, speaks English Martha -, daughter, 7, born in Alabama
The first three immigrated (per the census) in 1921 and were naturalized by the time of the census.I don't know if that is your family or not, but thought I would list it anyway.Naturalization records would be available from the National Archives branch in Atlanta.Go to www.nara.gov and there are links to this facility.
The National Archives in Washington would have the passenger arrival lists for Mobile from 1890-1924.You can order these online using a credit card, the link to their website is as follows: