You actually have a policy / security problem here. If employees are departing (for whatever reason), and the HR department is not notifying the IT department, then there are major security concerns. If an employee is let go (especially on bad terms), and his account remains active for up to 60 days, the potential exists for a great many problems.
I would go down a different path than trying to find a software process to delete inactive accounts. I would suggest that the managers of IT, HR,and security, get together and flesh out a policy whereby HR notifies both Security and IT about the departing employee. Keeping their account active for up to 60 days would be the same as firing an employee but letting them keep a key to the building or Security Access Card for 60 days after which it would self-destruct if not used during that time period. Also what procedures are in place to keep a fired employee from gaining access to his account (if it's still active), thus nullifying the60 day period of inactivity.
On the flip side, if you instituted such an automated process, what would keep it from deleting accounts of active employees who may not have accessed their accounts for long periods due to illness, vacation, etc.
This is probably not the answer you were searching for, but I think it is the safer, more secure way to go.
