I told him this:That's great that he's keeping it. A good guitar is more than wood, plastic and metal...
Suppose you sell it for 10K. Now you have no more guitar.
Then as sure as shit, that money will be spent - on whatever - some household shit, but not a guitar. Ten thousand dollars doesnt go very far anymore.
If it were 100,000 then you could maybe pay off your mortgage and thereby improve your whole life, but it is only 10,000.
Now you have no money and no 68 Strat.
Conclusion, never sell a guitar you love.