Then don’t buy the car, as this implies that piston rings are gone and it is a work which one has to do after 250,000km. he never changed the oils on time and there will be many more damages which you cannot see.
Not every owner has a knowledge, time and money to fix every issues in car. People normally knows how to drive the car and ignore many things thinking that new buyer will take care of it and will drive as long as car can stay on road.
This car will be more of a problem keeping it and you will have to rectify many things, not worth the time and effort. Secondly Honda parts are expensive so money which he is leaving will go back into fixing all these issues.
Second school of thought is that there are people who are in hunt of these sorts of cars provided its not accident-ed but these people knows exactly how to fix the problem, technically they understand everything and then they resell the car on higher price again.