Does anyone have a rough guesstimate on how much taxes would be for a roundtrip flight from Fort Wayne, IN to Edinburgh?

FWA - ORD - LHR - EDI (4/23 to 4/27)
(FWA/ORD is with AA with the others on BA)

I'm not the EC member (brother is) so the agent wouldn't give me the tax amount until the flights were ticketed.

Thanks in advance.