Modeling event or message in a event / message driven architecture

I'm modeling messages to be used in an integration among microservices. Did You ever seen a design pattern specific for messages?

For example, in message bellow , how could I represent if child with ID F123 was deleted?

There's a little trap, because I could send delete event from entity Son but in this case I just want kill the relationship between entity Father x entity Son. So, My event is an update in entity Father to delete the relationship with entity Son.

The consumer could do a diff between message and local data, but comparing every message with high data volumes could be very expensive.

{
   "header":{
      "op":"updated_father"
   },
   "body":{
      "id":"1234",
      "entity_type":"father",
      "childs":[
         {
            "child":{
               "id":"f123",
               "entity_type":"son"
            }
         },
         {
            "child":{
               "id":"f333",
               "entity_type":"son"
            }
         }
      ]
   }
}

thanks all!