Nothing that it needs is beyond what a reasonably determined amature can figure out with a bit of help from the group. I've been working on Volvos for 14 years, but when I first started I knew nothing about them. Through trial and error, a Haynes manual, and advice from the web I've become very proficient and donate a significant amount of my time to helping others maintain their bricks. As far as the engine goes, I wouldn't be surprised in the least if all it needs is some exhaust system attention or checking the order and condition of the plug wires. I've picked up several cheap cars over the years as-is with various problems, it's always a gamble but so far I've been lucky and it's been little things people overlooked and assumed the problem was much more serious. When I redid my A/C I knew nothing about it but found enough info here to figure it out. When I did the headliner I had zero experience there, but found tutorials online and jumped into that. Looking at that car, I think a good solid weekend of washing, waxing, scrubbing, polishing, and vacuuming will have it looking presentable, then he can tackle all the other odds & ends it needs. Put simply, I'd pay 600 bucks for it without batting an eyelid if I didn't already have more cars than I need.
Are you actually trying to help, or do you just get off by being an a-hole?