Your son needs professional help to learn how to deal with his losses. We as adults don't always understand death.....think of how scary this is for him. Get him help before this snowballs out of control and so that he no longer has to live in fear. I wish you both all the best.
I would recommend that you take your son to see his pediatrician for a medical check up, even tho I don't think there's anything physically wrong with him.
He lost, who I am assuming, was a very importand and major person in his life (the uncle) and also a close family friend, both at the age of 6. Losing two people we love as adults is overwhelming, but a 6 year old I don't believe can really understand death. I think they see it as abondonment. They just know that person they loved is not there anymore and some believe it's their fault the person "went away," or they fear that they may just "disappear" as easily. Even now that he is 8, his fears seem to be increasing. If he cannot be alone, if he is having night terrors, if he is saying to you "love family in case they my last words,"
This is a very troubled child who needs help desperately. After the doctor gives him a clean bill of health, get him refered to a child psychiatrist or psychologist who can help him deal with all those feelings he doesn't understand or know what to do with.............but are scaring him to death.
At 8 he isn't going to ask for help. He needs you to get it for him. I hope you do. He's suffered enough.
I wish you all the best
Peace
Greenlydia