Adrian got bullied by some teenager animal bullies outside the zoo, they jeers at him for being a strange hybrid and has homosexual parents,
his big brother Damion witness this and went raged, step forward bravely and fought those bullies by force.

Damion has a good grounding of martial arts he learned from his parents since he was little,

he did defeated some but they got multiple members and the boss is way much more stronger so he ended up hurt badly,
be beaten up and broke his wing and leg before his parents arrived and got them away from the dangerous animals.

Adrian was all guilty that he make his brother involved in this and be hurt badly because of him,
dislike violence and so he never wanted to learn any martial arts, too weak to protect himself, or his brother.

Skipper and Hans being proud at Damion but also trying to comfort their little son when they saw him desperately cling to Damion's bed and being upset like that.
Damion also trying to reassuring by showing how strong himself is and he'll be alright soon that Adrian doesn't need to be worried for him.