Ok so

Ok so. My heater core went out. And started dumping coolant inside the car (we were at the gas station where my friends cousin worked) one of his co workers said they were a mechanic on the side. Knew it was the heater core. He said he could help us fix it so it could run but we wouldn't have a heater. I agreed. When he went to fix it instead of taking the hoses and by passing the heater core he just blocked them off with two nuts. We drove the car. It would over heat. A couple days later we were driving it shut off while we were driving but a little bit before that we smelt a metalicy burnt smelll. We pulled into a gas station and the car wouldn't start. We got it to a meachanic he told me that the cylinders were caked with coolant and that's why it wouldn't start. He wanted to basically replace the engine. But said it would cost 4000 I can't afford that. Idk much about cars. But every one I have talked to and told what happened said it was a blown head gaskit. I know not much can readdy be fersher with out looking at it. But I would like second opinions from the info I gave. Thank you.