Delete all content
If the admin chooses to delete all the content related to the user being deleted, all comments and replies by the user for the pages and posts in your website will be owned by the admin thereafter.
For the comments/replies mentioning the deleted user in the content and for the comments where the deleted user is assignee (i.e. assigned for that comment), the username of the deleted user will be replaced by the username of admin. So, from now onwards, admin will be the owner and handler of these comments too.
Example: Let’s say, a user A had added comments on a page titled ABC and he was assigned a few comments in other pages. Now, if the admin deletes the user A, all the added comments and assigned comments will now be attributed to admin.