I have no connection to the Thormann family, but I have done quite a bit of resarch on Millhousen.
As you may already know, the Thormann name was sometime spelled as Coormann in the Millhousen records.Recently, I visited the Millhousen cemetery and saw a gravestone there for Henry H. and Mary A. Thorman.The birthdates are the same as in the Millhousen 1860 census (as reprinted in a 1984 Story of Millhousen booklet, except the years are different) for Henry Herman Coorman and his wife Anna Mary Feldhaus.
Looking at the info posted by Patrick Calihan in 2000, it seems clear that these Coormans and your Henry Thorman are the same family.Joseph is not listed in the 1860 church census because he was born a year or so later.There are, however, additonal children who are not on Patrick's list;John, born 12 Feb 1844; and Catherine, born 6 November 1846.
I'm not sure what other information might be of interest to you.I have access to the FHL microfilm of the Millhousen church records, and I could look up a few things for you.
Incidentally, the dates on the gravestone (& 1860 census) are as follows: Henry H. Thormanb. Sept. 24, 1811 (1814 in church census) d. Dec. 15, 1893 Mary A. (Anna Mary, in the census) b. Mar. 18, 1819(1821 in church census) d. May 4, 1899 The rravestone looks newer than the 1890s and probably is a replacement for an earlier one.