A task could have multiple sub tasks.
It is not necessary that every sub task is assigned to the same person. Multiple assignees could be assigned to sub-tasks of a task. It could also happen that the task is assigned to a person and the sub-tasks are handled by assignees exclusive of the parent task's assignee.
The problem is that when we check the backlog, the assignee who was assigned the subtask cannot see his ticket. Hence its not possible to decipher anything from reports.
Example:

This particular developer is assigned 9 tasks. The total amounts to 104 points which is correct.
The problem is that he is actually assigned 9 tasks and 4 subtasks. The 4 subtasks and it's story points are not counted here. I need to bring it here, so that the total story point estimation/ developer is correct.
Thank-you.