Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
Has he had continous vomiting for 2 months?
Since he is older, did they check any bloods? Did they try any treatment?
Can he keep any food down? Water?
Does he drink more then he used to or pass large volumes of pale/watery urine?
Does he have diarrhea?
Any diet changes? Access to toxins (ie chemicals, plants, etc)?
Are his gums pink or pale/white?