I'd probably tell them my name, and that I'd just found my cousin and he's dead, and ask them to send someone asap. I may or may not add that I'd come to check on him re; hearing the news about other family members being murdered, according to my level of anxiety at the time or the questions 911 asks folks. I probably would not have gotten close enough to the body to inspect him for a gunshot wound(s) b/c I'd have backed out of the trailer, got in my truck, and placed the call as soon as I'd seen the body. Then waited for the authorities, while calling my family, I may have even called nearby family first, so I'd not have to sit there alone, if I were alone to begin with. Jmo of how I think I'd react.