Advise a friend who respond to conflict by avoidance on why it is not healthy in sustaining positive relationship

Avoidance is not a good strategy of responding to conflict in a relationship: it will have the effect of weakening the relationship (if you keep on avoiding the person, your relationship might dissapear) and it will also potentially not solve the problems.

Avoidance might work in case of a conflict with a person with whom one does not have much in common, but not in a case of a relationship.