how come you are here?

In the previous chapter, we read that Sana and Grandma had a very superheated argument and Then Grandma stormed off out of the room while Sana sat there shocked, she was thinking:

Sana: What will Kashif think of us? That we are greedy people and grandma wants payment for me!? Is she selling me or marrying me off

Then she reluctantly went to her room and went to sleep. The next morning Kashif came to visit her for breakfast do you know why? Because Sana had texted him before going to sleep that she wants to talk to him about something important and for this reason, she had mentioned in the text that she is inviting him to breakfast tomorrow. So let's continue the story when Kashif came for the breakfast in the morning Grandma was shocked to see him, she inquired :

Grandma: Hey Kashif! I wasn't expecting you, how come you are here?

Kashif: Sana invited me

Grandma: Oh really

Kashif: Yes