peter kelly , 34 , was fatally stabbed on tuesday night at the st croix river .
levi acre-kendall , 19 , charged friday with first-degree reckless homicide .
max sentence is 60 years of combined prison and extended supervision .
kelly and friend were fishing on minnesota side of river and heard swearing .
asked three men on wisconsin side to be quiet and an argument ensued .
kelly and friend drove over to other side and the fatal stabbing occurred .
dead man , who volunteered as a high school wrestling coach in his spare time , leaves behind a wife and five children , all under the age of nine .