You have to approach this logically, which hasn't happenned so far.
You say it's running hot. How do you know? Temp gage reading high or hearsay? Fan coming on?? Thermostat?? Easy fixes.
Smells burnt. Is the front of the engine full of oil? My valve cover was leaking horribly, letting oil run down the front of the engine. Person selling to me had powerwashed the engine, so I didn't know until I drove it home on the freeway. New valve cover gasket....easy fix, even for the inexperienced.
Big thing is whether you have driven it as it was overheating, which could blow the headgasket and/or warp the head. Fix the overheating and then see if it uses coolant.
If you want to get the most help. Give us factual information, not yours or even the mechanics diagnosis. Like temperature gage reads at max......coolant boiling over......coolant being used......stuff like that. Not engine fried.
Good luck. Let's start over on this.