Can you please let me know if there is a way to disable user access to Adobe Analytics and still use the segments created by them. Also, Can I re-enable the user with the same segments and events when he was disabled?
The segments will remain if you disable the access (rather than delete the account).
If you want to delete the user account and keep their segments, then you can move the segments from one user to another. Go to Adobe Analytics > Admin > Analytics Users & Assets. Select the user and click Transfer Assets.