Just because it is not physical, it does not mean it is not abuse. Verbal and Psychological abuses are real things; their effect is perhaps more damaging on the mind of the abused than the open wounds that can be seen in physical abuse
Apart from intimidation, an aversive strategy adopted by domestic abusers is isolating their victims to manipulate. Isolation from the outside world is an important element of psychological control for the abusers to encourage compliance from the victims.
You may have noticed that your friend is acting differently, and you suspect they are being abused by their intimate partner. Help them to realize they’re in a relationship to be happy, to smile, and to make good memories, not to be constantly upset, to feel hurt, and to cry.