For me, buying used isn't about getting it cheap. It's about how you pay out the money.
Buying new, you put a lot more money up front on the cost. Often that means making monthly payments. When the payments end, you hopefully have a few years before you start putting out for age-related repairs.
Buying used, you put less money up front on the cost. However, you spend several years making repairs (age-related and failure to maintain). Then hopefully, you have a few years before you start back in with new age-related repairs.
What your friend has found are the "easy" things - they can be worked around until he wants to do the work and fix them. Hopefully he won't find "little" issues in the engine/chassis - those are the things that can't be ignored and can make using the rig difficult.