My friend had a CPU of +/- 250 now its sudently +400

Is there anything he can do to fix it?

The causes of high CPU usage are wide-ranging—and in some cases, surprising. Slower processing speeds could easily be the result of either the mybkexperience antivirus program you are running, or a virus that the software was designed to stop. ... Try either scanning with multiple antivirus tools or performing a manual virus removal.

The recent changes to the lobby cpu benchmark hit some people quite heavily-while you didn't bother to mention what his specs are, a new way to calculate the cpu score is being worked on afaik, but, as always, there's no ETA.

If his cpu is actually decent, he could always just say into the lobby what he's running, most hosts are reasonable and will let him play so long as he doesn't slow down everyone at 10 minutes for larger maps (otherwise, if he's not already, he'll just get blacklisted).

Correct - we're working on a small benchmark map. That way there is no theoretical score anymore - your score represents how fast your computer was able to finish the benchmark map, in seconds. The average should be about one minute.