Does he have any maintenance records? Does he claim to have done regular maintenance? Unless he has trashed it, I'd be surprised if it needed an engine anytime soon.
A friend once told me when looking at used bikes, if the seller's garage was neat, clean, and somewhat orderly and he said he did the maintenance then he would buy the bike and seldom have regrets. If it is a chaotic mess, and you have doubts about how well the bike has been maintained, stay away.
2015 DL650XT w/ factory Suzuki/Motech side cases and engine guard.
First farkle - Motech center stand
Augustus Wind Deflectors
Fat, foamy grips
Givi AirFlow windscreen
Go-Cruise throttle lock
JD Astar 1260 lumen LED tail light bulb
Suzuki (SW Motech) Top Case
Hyde Racing skid plate
Adventuretech kickstand foot, fork brace, fender raising kit, and peg lowering kit.
Zita 26mm up / 20mm back risers
Sit and Fly Seat Net
So God created man in His own image; in the image of God He created him; male and female He created them. Genesis 1:27