[I thought I was reading the Milwaukee board when I read/responded to your initial message - and there was no reference to Dane Co.]
For all practical purposes there was no active registration of deaths in 1849 Wisconsin at the city, county, or state level. Pennsylvania would've been far ahead of Wisconsin in its record keeping practices in 1849.
In Milwaukee, possibly elsewhere in Wis., births and deaths only became actively recorded (but not comprehensive) in about 1872. In general, index listings found previous to that year were reported retroactively by families.
In early Wisconsin, a church registry becomes a primary source for a birth or death. If nothing else, start by looking for a baptism of the last child you mentioned, or even church records for the brother's family, names of a baptism sponsor, etc.
P.S. The spelling "Rape" is an indication of what "Reb" sounds like when spoken by a native German.