I have this code to delete data from multiple tables in one go:
DB::table(\'tb_stikes_register_school\')->where(\'register_id\', $_POST[\'id\'])->delete();
Something like this maybe - haven't tested
DB::table(DB::raw('FROM tb_stikes_register_school, tb_stikes_register_guardian, tb_stikes_register_student'))
->join(ENTER JOIN INFO) // wasn't clear how your tables were related
->where('register_id', $_POST['id'])
->delete();
Or you could use a fully raw query:
DB::query('SQL statement here');
Basically recreating something similar to this: delete rows from multiple tables