car overheating question?

[Brenothy]

I'm looking at buying a car from a friend, but when I drove it for about 30 mins, it overheated and the water was boiling in the radiator. He's now told me it's fixed and has said it was the carburettor. As I don't know anything about it, I thought I'd see if I could get an answer here before I go any further. I'll take it to a mechanic before purchase of course, but would be interested to know if a faulty carb would cause that. Thanks