Reinstating a technician

By accident I removed one of our technicians today. A bad move.

Now he is reinstated I am trying to re-associate him with his past closed cases. The only way I can see of doing this is along the lines of a filter of closed requests based on the history entry that still bears his name. Can a filtered request list do this?

If not, can it be done in SQL?

Also, we have 106 sites and although I have re-instated him to each of the sites, other settings such as the notifications and the chase up emails he has been removed from. Is there a way to globally re-add him back in to these settings rather than have to go to each site within the group and alter it there one by one.

Thanks in advance - Terry