Three possibilities in order they should be executed next time...
1) Search the forums
2) Read the CreateUnit tutorial
3) Ask Mr.Peanut "xxxx" createUnit [_pos,_grp,{BOBs=this ; this addEventHandler ["killed",{_this exec "enemykill.sqs"}]},0.5,"PRIVATE"]
If the script "enemykill.sqs" or "isdead.sqs" or whatever you call it _this select 0
will be the dead unit.