Son is thinking of buy this for his first car.Needs to get him through highschool (next 4 years).This Cougar looks nice inside and out.. seems fine.. but l dont know much to tell him what to look for.They are asking $3999, I am sure we can talk them down considering deal is cash.What is your opinion?

Free opinions are worth what you pay for them. Being unable to see,drive or check out this car myself just gives me the info you offered, so do not expect much in return.
You can check out kelly is blue book for reasonable estimates of the car is resale value (you can find it on line). Have a reputable mechanic check it out for possible trouble areas and if it checks out ok, go for it. Otherwise, buyer beware.

check the car take it for a drive, see how it handles dose it over heat. get it to hyway speed dose it shake wobble. look under the hood any major leaks, under the car dose it have a tranny leak if so how bad. stuff like that look at the oil dose it have water in it is it black or is it brown. stuff like that. try to get it for 3 but if not then 35oo should be fine.

My thought is can u afford to dump 2 grand more into it to make it good as new? with that kind of mileage there is certainly going to be emissions equipment needing replaced & suspension parts worn. possible heater core and/or radiator replacement depending on how well the car was maintained. they r a great car comfort Wise. I'd take it to a very reputable mechanic who will run an emissions test, coolant sample analysis & oil sample analysis as well as a thorough suspension system check.