Death record names his parents.

1910 Census, Rochester, Beaver Co., PA, April 30, 1910
Grim, Isaac N., 34, m. 7 years, b. PA, parents b. PA
Margaret H., wife, 28, m. 7 years, 4 children/3 survive, b. WV, parents b. WV
Okley, son, 6, b. PA
Howard E., son, 3, b. PA
Kenneth A., son, 9 mon., b. PA

1920 Census, Harris Dist., Wood Co., WV, Jan. 14, 1920
Grimm, Isaac N., 43, b. WV, father b. PA, mother b. WV, farmer
Margaret H., wife, 31, b WV, parents b. WV
Okley, son, 15, b. WV
Howard, son, 12, b. WV
Kenneth, son, 10, b. WV
Leonard, son, 7, b. WV
Edith, dau., 5, b. WV
Dorothy, dau., 2 y, 11 mon., b. WV
Everett, son, 2 mon., b. WV

1930 Census, Lubeck, Wood Co., WV
Grimm, Isac M., 54, b. PA
Margurete, wife, 42, b. PA
Oakley, son, 26
Howard, son, 23
Kenneth, son, 25
Leonard, son, 17
Edith, dau., 16
Dorothy, dau., 13
Everette, son, 10
Esther, dau., 8
Robert, son, 2