I believe that this Henry Sleep is the son of John (1805-1847) and Mary (nee Cornish) Sleep (1807 - aft.1871) from Egloskerry, Cornwall. Most of this family appears to have immigrated to Canada after John's death. Henry appears to moved on to Mineral Point, Wisconsin in the early 1860's and served in the the civil war. After the war, his older brother John (1831-1897) also moved nearby to Wisconsin. While Henry and his family moved out Iowa, John and his family stayed behind in Lafayette county, WI. I've meet with some of the descendents of John Sleep in Darlington, WI. They talked about having family reunions with the Iowa Sleeps about 50-60 years ago. You can obtain the civil war and pension records from Henry Sleep from NARA.
Good luck and good hunting, Richard Sleep