I updated your queryobj.php file to accept the date 0000-00-00
I can't seem to get the year removed field to accept the 0000 value... It is because your data type in the database is Year(4) and it appears that mysql is interpreting the date '0000' as '2000' automatically.
I got it to enter null if the field is left blank.. maybe you can use that as an alternative to identify lost members.