Your question is not clear ,you want it after
6 days or 60 days
????
You have to set one field having name
UpdatedAt(DateTime)
in your database table in which password is updated.
at a time of login you have to check if the difference between updated date and current date is greater than 6 or 60 as you want than you have to show message that you have to change password
you can get difference by this query
select datediff(day,updateAt,GETDATE()) AS TimeDiff