It's a mate's car (98 Saab turbo)....I said no, but could blow the h/g if overheated (if not already gone, which I thinks what's wrong).....it's the coolant in the exp tank, keeps dropping

I would say the same as you. If there is no visible signs of a leak with fluid under the car after it's been parked up and left to cool down 

ditto - ooooh Ive come over all Patrick Swayze

ditto - ooooh Ive come over all Patrick Swayze

That couldn't have sound worse no matter how many time's I read it back to myself.... Maybe it's just me ;) 

No, even if the stat is faulty, it doesn't produce a hole for the coolant to escape from.

HG is the suspect. Tell him to go and get the coolant 'sniff tested' at a garage.

He did and went from blue to green so h/g's buggered

Sorry to hear that :(