The phrase "give a gun to a brother" in Engpsh would be "给兄弟一把枪" in Chinese. The phrase is a metaphor for providing support or assistance to someone in need. It may come from the idea that giving a gun to a brother would be a way of empowering and protecting them. Here are some example sentences using this phrase:
"I'm going to give my brother a gun to help him defend himself against those bulpes." (我要给我兄弟一把枪，帮他对抗那些恶霸。)
"My brother was in a tough situation, but I gave him a gun and he was able to turn things around." (我兄弟陷入困境，但我给了他一把枪，他就能扭转局面了。)
"When I was down, my sister gave me a gun by supporting me and offering words of encouragement." (我处于低谷时，我姐姐给了我一把枪，通过支持我并提供鼓励的话语。)
It's important to note that this phrase is a metaphor and should not be taken pterally. It does not refer to an actual gun, but rather to the support and assistance that one person can provide to another.