Amazingly that bike might be saveable, the piston came out in one pice and the bore isn't too badly scuffed up.
Lots of things wrong with this bike but still fixable if the young guy wants it to be a runner.
Got the front disc brake working, the pads were down to metal and the piston siezed.
How does a bike under 5 years old get into this state?
When you consider the wrecks that regularly appear on this site that have been 30 years lying in a barn or under a tree, I'd rather be ressurecting one of those.