my son has a blown head gasket. Would it be worth it to scrap the car or repair?

What is your question?

We took it to Pep Boys and they replaced about 800 dollars of stuff but afterwards the engine light came on and white smoke was coming out of the tail pipe. We took it back and they said we needed to replace some valves for another 300 plus dollars. We then took it to Nissan and they told us the truth. IT WAS A BLOWN HEAD GASKET. So my son is already 800 plus dollars in ....nissan suggested that we repair the head gasket and sell it.