Recently my bros civic stalled out after a severe storm and was wondering if the engine is completly done....

He was driving home from work and the streets were flooded, he said it only reached up to the middle of the side skirt and the only reason he went through was because a cop told he to go through but he didnt want to because he didnt think he'd make it and wanted to make a u-turn but the cop didnt let him and so he went through and the car stalled. We took out the spark plugs and bought new ones and while they were off we started the car to drain out the water. The car wont stay on unless the rpms are above 2000. My concern is wheter or not the engine is still good?