The first spelling of Helman was Helmar. I am suspecting it is more likely a version of Helman (Hellman, or some other spelling).
What we know so far about Lydia.Her maiden name is Helmar or more probably Helman (Hellman, etc). (Bio of son Geo, Summit OH)
She was born about 1793 in PA (1850 census)
She married Christopher Helfer (probably about 1816 in PA but no proof yet)
Her first two children were born in Centre County PA in 1818 and 1820.
The family moved to Wayne Co, OH in 1820 (not there in 1819 OH census but are in the 1820 Census of Wayne Co OH, also states that in the George biography).
Further children of Christopher & Lydia were born in OH (many say Ashland Co)
I need to check when the counties were formed and how.
I believe Lydia died in Aug 1850 and is buried in Congress Cem, Wayne Co., O. There is a grave stone there but it was indexed as the wife of "G" but It looks like a "wife of C", to me but difficult to tell.
From The History of Ashland Co., OH (1863)
John Hellman emigrated from Centre Co., PA, and settled in Perry Twp, 17 June 1818. He purchased of Elijah Charles the SW quarter of section 3, which land he improved, and has up to the present date, made his home. His family, at the time of emigration, consisted of his wife and three children, viz: David, Mary, and Catherine. The first mentioned is now a resident of Jackson Twp; Mary is the wife of Daniel Eshelman, of Lafayette, and Catherine is the wife of George Walkey, of Perry Twp.
notes: Could this be Lydia's brother, or other relative? He & his family came from Centre Co., PA at abt the same time as Lydia & Christopher which makes me think there is some sort of a connection.