From the marriage we know that the father of Wilhelm was Ole Brorson. Farmname was Store Sl... (I could not read more of the name.)
I don't know much about searching in Sweden, but on Familysearch I found this Vilhelm Olsson born May 6, 1841 in Store Slagarp, Malmøhus, Sweden. Malmøhus län(county) is in Skåne.
Parents: Ole Brorson and Anna Andersdotter.https://familysearch.org/pal:/MM9.1.1/V711-3QS