Twilight doesn't have a brother. Shining Amror is her cousin. He sometimes drops by. She used to play with him a lot but they grew their seperate ways.

Cadance is very important for Twilight. Cadance is somewhat of a mentor figure. Unlike the reserved sometimes pessimistic Twilight, Cadance is outgoing and optimistic.

(Cadance even unironically ships Sparity saying Spike might grow to be a handsome dragon.)

Read More