Asking about worth is a tricky thing with old cameras.
To be honest, in many ways the old C series LENSES are worth more than the bodies! You can use the lenses on many bodies. Which is nice.
Overall the lenses are pretty cheap to get though. Doing a quick search on E-Bay the average price seemed to be about $75.00 per lens. Even for the 180mm. Not bad. But at that price should you get a "new" lens or fix the old one?
Fix the old one.
If the glass is clean and clear, and everything else seems to work, get a CLA on the old lens.
All of these lenses are OLD. Which means every time you buy one, you run the risk of getting one that is on it's last legs.
By having a CLA done by a reputable shop, you will run less of a risk of anything breaking while you are shooting. You need to get a CLA done anyway every year or so (depending on use) anyway. Drop a few bucks on a decent CLA and you should be good to go.
Then, if your friend likes the camera (I have two C3s...love them), he can always save up and drop $150.00 on a used body with lens and upgrade in quality while expanding.