Twitter issued a statement to The Verge and it reads as follows,
As part of our commitment to serving the public conversation, we’re working to clean up inactive accounts to present more accurate, credible information people can trust across Twitter. Part of this effort is encouraging people to actively log-in and use Twitter when they register an account.” Twitter also adds that “We have begun proactive outreach to many accounts who have not logged into Twitter in over six months to inform them that their accounts may be permanently removed due to prolonged inactivity.
Apparently the account deletion process will take many months to happen. Twitter is yet to mention when the deleted username will be up for grabs and whether or not there will be a cooling period in which the username is not available for anyone else.
The worst part is that the cleanup drive will also have an impact on the deceased. Unlike Facebook, Twitter is yet to offer a way to memorialize someone’s Twitter account once they pass away. However, Twitter assures that they are “thinking about ways to do this.”
Online services typically undertake cleanup drives to delete inactive accounts. All you need to do is log in once and you are good to go for another six months. Perhaps this is a good chance for you to grab a dormant username once the account is deleted.