MANKATO — The family of a former Minnesota State, Mankato, linebacker who was allegedly assaulted by a former Minnesota quarterback and another man has released more details on his injuries.

In a statement released Saturday via Mayo Clinic Health System in Mankato, the family of 24-year-old Isaac Kolstad said he required emergency surgery Tuesday to relieve brain swelling. It said doctors removed a significant amount of brain tissue that was no longer viable. And it said his lungs sustained severe injury, leaving him unable to breathe on his own. He remains in critical condition.

Prosecutors have charged 20-year-old former Minnesota quarterback Philip Nelson, of Mankato, and 21-year-old Trevor Shelley, of St. Peter, with assault. Shelley is accused of punching Kolstad early last Sunday. Nelson then allegedly kicked Kolstad in the head.