Can your friend "cheat or beat" the market now in old furniture? Sure but, you wont do it at a dealers or auction house, you will have to market it privately and FIND the right buyer which, is a lot easier to say than do these days.
I collect early stuff, 17th & early 18th century american furniture. 15 years ago or so, i stumbled upon a 1680 joined american chest of 3 drawers, inlaid with walnut & holly, side hung drawers in very good condition. This chest had been in the Bolles collection ( the Bolles collection is the foundation of the metropolitan museum of art in NYC, The American Wing was built in the 1920s to house his collection of furniture), it exhibited at the MET from 1929-1939. In sum, this was a killer chest with an impeccable pedigree and the dealer wanted 40k for it, to much for me so i passed. 2 years ago, i saw this chest again, different dealer and the price? 10k, thats a 75% drop in price in a little over a decade. The first dealer had put it up for auction and got $7800. hammer price to the dealer who now has it, add in 20% BP which takes you to $9300. and it is still sitting in inventory of the second dealer 2 years later and can't sell it for 10k which is really a break even price for the dealer who now has it.