A gay couple in Sherman Oaks, California are in critical condition after being stabbed during an argument with their son.

According to local ABC affiliate KABC, the couple, Ken Coll and Tom Boulet, were transported to a nearby hospital, where they underwent surgery.

The couple's adopted son, Matthew Boulet, 21, admitted to police that he stabbed his fathers. He is facing attempted murder charges. Police described Boulet as “nonchalant” while speaking with police about the incident.

Boulet was home from college for the summer.

Neighbor Florence Riggs told the outlet that the couple adopted their son when he was a boy and described the men as “great models of parenthood.”

Authorities are investigating reports that Matthew Boulet was suffering from mental illness.