Yes, From Client events will be done by AH to SQL. But you can't push anything from Agent Handler if ePO is down. It can accept the updates / Events from clients.
Is that means epo still need to deploy plicy to all client even there is agent handle.
Maybe this helps;
"The handler provides updated site lists, policies, and policy assignment rules just as the ePO server does, and also caches the contents of the master repository, so that agents can pull product update packages, DATs, and other necessary information."
After shutdown EPO server Agent Handler still handle policy, task and other issues.
I tried it Works fine.
1. Shutdown EPO.
2. Uninstall VSE.
3. Then delete all directies/files about VSE.
4. Install VSE manually.
5. Open McAfee Agent Monitor, click Collect And Send Props and all tasks added and policies changed.
But without EPO we can't change policies and tasks.
And If you didn't choose AH as secondary Agent Handler at Agent Handler policy, clients doesn't communicate AH.