XP is receiving less and less support, and the time for when it will stop being supported altogether is coming up fast. Linux on the other hand is being continuously worked on.
A more fair comparison would be to ask if he was still using the same distro without doing any updates from the same time the last update to Windows XP was released(which still isn't even fair because it assumes that the updates solve the exact same thing, which they are clearly not).
apple and oranges, mate. linux is not a monolithic release like windows XP. its thousands upon thousands of individual programs pulled together ad hoc and at will. My kernel is less than a few hours old, but my version of some software is 7-8 years old.
A more fair comparison would be to ask if he was still using the same distro without doing any updates from the same time the last update to Windows XP was released(which still isn't even fair because it assumes that the updates solve the exact same thing, which they are clearly not).