watermelon wine fail

[Phathead]

info as I understood it from a friend of my wife. he attempted 200lb plus of water melon into wine. it tasted like crap so it has set in airlock carboys for over a yr. 11 gallon at 16%. he has offered it to me to do as I wish. being new to this, the only thing I can think of is fill boiler with it and water in thump for stripping run(s) to a netrual. any other ideas?