My border collie is 7 years old and all of a sudden acts like he has no will to live. He has not eaten anything for about 7 days. Not even things like pure tuna or hamburger which any dog would suck down so fast. He has lost a lot of weight and will only come to his name if you say it repeatily. This is a highly intelligent dog and I hope that he will be OK. We are taken him to the vet again tomorrow. He will at least drink water if I put it in my hand for him to drink from. He seems to vomit about 4 times a day. I hope that my buddy will be OK..
Does anyone have any advice to give?

It does not sound too good. Best wishes to your buddy and you as well.