Chris Massey has a swollen face and a gash on his head after a brawl with Lil Twist -- but he and his bro Kyle Massey aren't backing the bus over Justin Bieber's pal ... not yet, anyway.
We broke the story ... Chris claims he got robbed and beaten up by someone with brass knuckles at Kyle's home last week -- and Twist is now a felony robbery and battery suspect.
We got the Massey bros at LAX Wednesday and asked about the incident ... which landed Chris in the hospital. For some reason they're going out of their way to go soft on Twist.
Seems a little late to kill him with kindness.