It's 15 years old and is a nine speed. I'd offer him somewhere between $150-$200. He might be offended, but it's not worth much more than that. Make sure it's your size.
Both of my TitanFlex road bikes are about that age and are perfect and I think they are the one of the greatest road bikes ever made, but they are still only worth a few hundred $ at most. However, one has over 110,000 miles and the other has over 50,000 miles. Miles mean almost nothing, unless the frame cracks, like mine did at 105,000 miles. I now have a new frame and the bike lives on.