Aaron Guilbault (GILL'-boh), who is 33, admitted to hitting his father Timothy in the back of the head with an aluminum baseball bat two years ago.
The son was charged with second-degree murder, but his lawyer argued that he wasn't criminally responsible due to mental illness.
Justice Monica Bast said she accepts that Guilbault's schizophrenia symptoms had been escalating and that he didn't know that killing his 58-year-old father was morally wrong.
Guilbault is to remain in custody while a review board decides what, if any, treatment he needs.
Timothy Guilbault, a former Red Deer city councillor, was found dead in a home near Innisfail and charged with second-degree murder.
The Crown had argued that psychotic episodes or schizophrenia do not necessarily excuse an accused from responsibility in a crime.