£2000 isn't a lot of money for what could be a whole lot of fun.
I'd get it professionally checked over, and if it's good, deduct the money from the sale or haggle over Sale with valid MOT only.
You really need to see back MOT's and paperwork to verify mileage etc.
I'd certainly take a look, but be prepared to say no and walk away if there's signs of problems.
Why hasn't he put it through an MOT?