The victim was originally transported to a London hospital with life-threatening injuries but was pronounced deceased last week.
The victim is identified as 57-year-old Kevin Richman of Huron-Kinloss Township.
A 26-year-old male of Huron-Kinloss has now seen his charges upgraded to manslaughter.
The accused remains in custody.
The South Bruce OPP and the OPP Crime Unit continued to investigate under the Criminal Investigation Branch.
If anyone has information on the incident they are asked to call the OPP or anonymously to Crime Stoppers.