He is just the way he is! He's a nice boy that talks about pirates and of course ships!
By helping her with a test of ships he knows a lot about Breeze. Him and Breeze have a nice relationship between each other even though they don't know everything!
By knowing a lot about Dream he decided to be friends with her!(aka Dream was his first friend) She and Matey have a club together by collecting just rocks!?(I don't even know if they collect rocks)
Whispy has a crush on Matey just because he wanted to go on a date with her in the future! That was the day when they fell in love!