Sunny, magic cannot arrange a relationship. But it can be used to open up a person to the possibility of a relationship. However, it is the participant(s) in the exercise to that effect who will experience the change, at least much more easily than an outside party.
Your friend actually can cast a spell herself, as a spell can be cast by anyone. But don't forget: A spell is not magic, nor is magic spells. A spell is one method some people use to attempt a magical result. Understanding how it works is a very important factor to practicing magic.
Perhaps your friend needs more a boost in confidence to speak to the boy she likes, and confess her feelings towards him. Speaking to him plainly would be the most likely successful thing to do in this situation.