Crikey Roxymm you poor thing! I don't have any personal experience with a baby of your age, but here are a few ideas (and I'm sure you've tried many of them!)
Put sippy cup, doidy (a couple of different types, colours etc) in with DS's toys for a week or so, so that he knows they're fun and nothing to be scared of. Gradually introduce some water and see how far it can get thrown then see if he'll take some milk from DP.
Sounds silly, but let him see you and DP frequently drinking milk from a similar cup - babies quite often just want to do what mom's doing. If you offer water in a sippy cup when he's eating, try putting milk in the cup while he's not looking! or gradually introduce milk diluted in water (blerg! but might work!)
Try different temperatures of cow's milk? Try when he's very sleepy, or relaxed...
Put him in his cot to play for an hour every day, so it's not seen as a scary place to be. If he does nap in there after a few days, potter round the room so he knows you're still there, then gradually withdraw.
Have you read any of the No Cry Sleep Solution by Elizabeth Pantley? Very gentle ways to get baby to sleep more independently. It sounds like sleep is at the heart of things at the moment.
Is his cot in your room or his own? Try having a couple of nights (hard ones, though, so be prepared!) where your DP does ALL the settling. Even if it only works for 10, 20, 30 mins at a time. If this means putting a mattress in DS's room, then so be it. Have him offer water if desperate, but try your darndest not to go in (sleep with earplugs in - DS will be fine. He's with his dad). Might take a week or so for him to realise he doesn't need boob to get back to sleep, so steal yourself for some more sleepless nights that'll hopefully pay off later.
Get plenty of contact time with DS during the day (which must be more and more difficult as your bump gets bigger!), lots of cuddles and skin time - tank him up on mother-love before bedtime.
I'm afraid I don't know much about cessation of BF-ing other than it shouldn't be done too quickly. It's further complicated I guess by the fact that almost as soon as you stop BF-ing DS, your milk will be gearing up for your new arrival! Hopefully someone will be along to let you know how this might work.
All bests.