I REALLY need your help, family issue?

Im 17, but 18 in 3 months. My cousin is 17. He went to texas with my other cousins, for an unknown amount of time. He called me (Private) i recognized his voice though, he said he was goin to kill me and my friends when he returned. He is a person with nothing to loose, and really, something to gain. I , on the other hand, just Graduated high school and enjying life, but with this threat, now im thinknin if life really is worth livin. I could end up deaD or in jail. He is also somewhat involved in gangs, so if i take him out, his little posse might hunt me down. Im not scared or anything, just angry. I know he is unarmed, but i have a baseball bat with nails and could probably get another weapon becasue most of my friends are 18...So, how do we resolve this?