Hi,
iChat or Messages to a Browser has never worked.
He needs to get a Mac or you need to change to using a Browser.
The Why.
Google talk run a Jabber server.
Most Jabber App have a module call Jingle Library that does the A/V stuff. See Jingle
Jingle use different A/V protocols to those used by iChat and Messages.
The linked article seems to get changed fairly regularly.
Currently it reads
Jingle is an extension to the Extensible Messaging and Presence Protocol (XMPP) which adds peer-to-peer (P2P) session control (signaling) for multimedia interactions such as in Voice over IP (VoIP) or videoconferencing communications. It was designed by Google and the XMPP Standards Foundation. The multimedia streams are delivered using the Real-time Transport Protocol (RTP). If needed, NAT traversal is assisted using Interactive Connectivity Establishment (ICE).
As of December 2009, the proposed Jingle specification has not yet been approved by the XMPP Standards Foundation, but is now a Draft Standard, meaning: "Implementations are encouraged and the protocol is appropriate for deployment in production systems, but some changes to the protocol are possible before it becomes a Final Standard."[1]
The libjingle library, used by Google Talk to implement Jingle, has been released to the public under a BSD license. It implements both the current standard protocol and the older, pre-standard version.
I have bolded the last part.
This article has reads that Google (And XXMP/Jabber) "Created" the Jingle process. In the past the wording around this has varied and the implied involvement by Google has varied along with it.
Before that it did not mention Google in that way and also said the Google version was not that compatible with versions in other Jabber apps.
This "Older" version would be 3 years out to date.
iChat and Messages connect using SIP (Session Initiation Protocol) for A/V chats.
This works with an Intervening server acting as an "Telephone Operator" at both ends to check the Acceptability or the Incoming call and the ports to be used (it also checks that where the Visible Invite went is the person replying/Accepting).
AS you both have Google IDs in may be simpler fro you to use a web Browser and download the Google Web Browser Plugin.
NOTE:
This may have issues if you use the FLASH Plugin as well.
At one time Google Used Flash to generate the Video and it seems their plugin is very closely "related" in the way it works.
9:37 PM Friday; February 1, 2013
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously