One of my close friends is having a hard time weaning her 2 year old at the moment too...and she also eats very little. I don't think you can keep going on hoping that he will wean himself so pick an approach and then stick to it, as hard as it will be. Hopefully it only lasts a few days, so make sure you have heaps of support and its a time when there isn't too much else going on...

Another friend put vinegar on her nipples and told her 2 year old that boobies were sick and she couldn't have her milk...her daughter hated the taste and kept saying "poor boobies sick." It worked!

Good luck