Several prosecutors have requested that a Michigan judge restrict communications between James and Jennifer Crumbley during court hearings.
This happened after both, charged with four counts of involuntary manslaughter, were caught blowing kisses and muttering "I love you".
His son, Ethan, has also been charged with four counts of premeditated murder, among others.
The incident occurred in November after opening fire at Oxford High School, killing four students and wounding six others and a teacher.