I'm afraid he'll have to initiate a calendar reform to achieve that
There are three problems with that date: no day zero exists, no month zero exists, and actually, no year zero exists in the Julian/Gregorian calendar, though the last one is probably not enforced by at least some datetime libraries.
So, that date can be represented neither in the database, nor in a datetime representation in any reasonable language. My opinion is that it is therefore impossible. The only possibility I see is to choose a special value (such as NULL) and represent that value in the user interface as "0000-00-00 00:00:00". Though displaying a "null" or empty field instead would be probably even better.