PLEASE HELP, MY BROTHER WAS ROBBED!?

A couple hours ago my brothers "friends" (they are all gang members who carry guns, and have been in trouble with the law several times) came to my house and asked to borrow my brothers brand new phone for an emergency. My brother agreed and handed the phone over to the guy (he is like 24, my brother is 16) the guy ran away and took the phone with him while saying is you snitch i will kill you and your family!!? I am 12 and i am too young to die. Please help we talked to the police but my brother is scared and wont say a word because the guys will send "people" for them.