White smoke coming out of exhaust, smells like coolant and it overheated

What is your question?

I just bought this truck from someone and those are the problems on the truck. Previous owner thinks that it has a blown head gasket. But he said that there is white smoke coming from the exhaust and it smells like coolant, he took it to Firestone and had a radiator and thermostat put in and it over heated the same day. Any advice?