I'm not sure about his wife's name. I found a Carl Witt married to a Lena Waebeman 24 Mar 1882 in Delaware. I'm not sure if this is your Carl though.
I also found this story that someone posted on ancestory.
The Early Settlers of St. John's Parish at Union Hill in 1867
The biography of the Carl Witt family is indeed one that portrays the spirit and determination of the pioneer settler even under extreme difficulties. It is filled with savagery and tragedy as well as with happiness.
The Carl Witts and their four children came from Wangerin, Germany to LaCrosse, Wisconsin in 1857. Wangerin was located in the state of Pomerania in Protestant Germany; approximately 125 northeast of Berlin. Today the community is located in Poland.
While in Wisconsin, Mrs. Witt passed away. Carl was married again to his deceased wife's sister and in 1859 he moved the family to Brown County, Minnesota. Shortly afterwards they began farming in the Birch Coulee area of the Minnesota River Valley in Renville County near Morton, Minnesota. They were located near the Sioux Indian Reservation and so became acquainted with many of them on the reservation. In 1862, the young Sioux braves, angered by the past misdeeds of the white man went on the war path determined to kill all white settlers in southern Minnesota. Many white settlers were killed including Mrs. Witt as the warriors headed southeast to attack Fort Ridgely.
The following is the story of this tragedy as told by one of their children, H. Carl Witt:
"It was about noon. Father had gone some distance away to cut hay and my brother William had brought home a load with the oxen a short time before. My stepmother was stacking the hay in the yard and William was unloading it when five Indians appeared. They had on warpaint and carried guns, but were on foot. We had a big dog that always made for Indians and when my stepmother saw them coming she got down and caught the dog and tied him up, as she always did when Indians came. But they walked up to the stack and without saying a word, shot my stepmother in the breast. She died almost instantly. William jumped down from the wagon on the side opposite the Indians and ran into the woods. We children were playing near the cabin. My oldest sister, Augusta, was working in New Ulm. There was an opening for a cellar beside the cabin and I was standing beside it when one of the Indians leveled his gun at me. One bullet struck me in the back of the head and another entered my left hip. Although I was not quite eight years old, I knew enough to lie still when I fell. I had fallen into the cellar opening. The other children had hidden in a little smoke house father had built.
"For some reason, the Indians didn't stay to kill the rest of us. They probably thought I was dead and may not have seen the others. Anyway, they didn't stop to take any scalps but hurried on, perhaps to attack some other family. William had hidden in a hollow log in the woods, and, wounded as I was, I ran with the other children to find him. He went after my father, who came home at once. They buried my stepmother where she had fallen and we packed up and set out for Fort Ridgely with the oxen. At the fort, a doctor removed the two bullets from my head and my hip. It seems that the bullet that entered my head had glanced and did not penetrate deeply, while the other had caused only a flesh wound.
"We stayed at the fort until the worst part of the fighting was over and then went to New Ulm. We remained there awhile and then went to St. Peter and from there came to Belle Plaine, where we were housed in a warehouse with other refugees. If it were not for the small cannon at the Fort we would all have been killed.
After a brief stay in Belle Plaine, the family moved to Union Hill in 1863 where they settled on the Franz Giesen farm. Carl later married Mrs. John Giesen, a widow with two children. Her husband had died shortly after finding his brother, Franz, dead under a fallen tree.
Mrs. John Giesen (Helen Hoffmann) was born in Dollendorf, Germany, to William and Sybilla Hoffmann who brought her to this country in 1854. She married her neighbor, John Giesen and lived on his farm until his death. They had two children, Frank of Union Hill and Mrs. John Lenz (Elizabeth) of Ellsworth.
Carl's family consisted of four sets of children. To his first wife were born four children. They were William of Shakopee, Mrs. Joseph Hoffmann (Augusta), H. Carl, and Mrs. Peter Klinkhammer (Louisa) of Union Hill. His second wife bore him two children, Joe of New Ulm and Mrs. Peter Bettendorf (Mary) of St. Cloud. His last marriage gave him two foster children and four of his own. The four were Mrs. Tom Lenz (Margred) of Ellsworth, John of Omaha, Henry of Union Hill, and Mrs. Math Seuer (Helen) of New Market.
The Early Settlers of St. John's Parish at Union Hill in 1867 By Victorin J. Ruhland June 1967
New York Passenger Lists, 1820-1957 about Carl Witt Name: Carl Witt Arrival Date: 4 May 1857 Birth Year: abt 1824 Age: 33 Gender: Male Ethnicity/Race/Nationality: German Place of Origin: Germany Port of Departure: Hamburg, Germany Destination: United States of America Port of Arrival: New York Port Arrival State: New York Port Arrival Country: United States Ship Name: Donau