Originally Posted by Chris142
Let him deal with it. No good deed goes unpunished.
^^^^^ This.
Unfortunately hes happy with or doesnt care about the engine oil like it is leave that be. Tell him that he will junk the engine if he hasnt already and that you know of ways to try to undo the damage but let him know the negative things that can happen first.
You could plug a passage then starve a lifter, valve guide or timing chain. You could also uplug a sludge coating that is preventing a leak so cleaning it could cause leaks or consumption of oil if the rings are crudded up.
If any of these things happen you could be blamed for bringing on the problems with your doctoring.
Most likely, he'll say no just leave it, its fine.
Frequent oil changes is about all I would suggest if its not my car.