Correct. I have no faith that a 6.5TD would go 250-300,000 without a major overhaul. If it's already got 220 on the ticker, then it would be too close to grenading for my comfort level.
I assumed he didn't want a truck that will have engine problems pretty soon.
If he only drives it a couple thousand a year, then yeah, maybe it's worth a chance, roll the dice, but ya gotta make an observation: Why would a guy sell such a nice truck if he just replaced so many engine parts on it? When someone sells a super nice diesel pickup for $3,200, that tells me something's up. However, If he only pays $3,200, he could get a newly remaned 6.5TD for ~$5,000 so it wouldn't be too bad if he doesn't mind the likely hassle & the downtime.
With 220K on a diesel truck, I'd be looking at a 5.9L or 7.3L to avoid replacing the engine, which could happen at any given time with a 6.5TD. They're just not as "hard" as a 5.9 or 7.3L which you might be able to get for $5,000.