2 Sorry you two are having a rough time of it right now.
You'll probably get more responses if you post in one of the breastfeeding forums. You could ask a moderator to move this to one of them for you.
I'll try to help if I can though...
I would really only nurse him if he's eating (getting milk). It sounds like he wants to eat (nurse) but is in too much pain to. Usually when they're teething and they start nursing it brings more blood circulating through their mouth and intensifies the teething pain.
So, I think the most important thing to do would be to take care of the teething pain. Then he'll be more relaxed and able to nurse. I've had great success with Gummirub. I believe I got it from Whole Foods. It's tastes absolutely terrible but it numbs their gums completely. Also, you could try (as weird as it sounds) a bag of frozen vegetables. Let him chomp on those a bit and then when it's numbed him try to nurse him.
Don't let him latch on until his mouth is wide, wide open. It will take patience, but he will do it eventually if he really wants to nurse/eat.
I'd really recommend going to see an LLL leader too. She can give you some in person help and support.
I hope things get better for both of you very soon. It will pass.