Per the below referenced book: "He received his portion of his father's estate in 1783. Lived in Plumstead Twp. at what is known as the burnt mill, where he followed the occupation of miller. Children: Abraham, Isaac, Anna, Mary, Elizabeth, Jacob, Mary, Barbara, Hanna, Margaret."
Book: Brief History of Jacob Wismer and a Complete Genealogical Family Register of his descendants from the earliest available records to the present time with portraits and other illustrations by Rev. Abraham James Fretz (introduction by Eli Wismer of Plumstead, PA) Mennonite Publishing Co 1893 (Page 8)
It may be possible to confirm family relationships with Jacob by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Jacob: