To stick up for やり返す

To stick up for

to protect/defend (verbally or physically)

言葉や動作で言い返す／やり返すこと

"When I was young, my older brother always used to stick up for me. If anyone was trying to hurt me, he'd defend me."

「子供の頃、いつも兄がやり返してくれた。誰かが僕を傷つけようとする時、守ってくれてたんだ。」