Hello Carol, I am afraid that the expert you have requested is not currently available. Still I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
If you would like my help, can you tell me:
Have his vomits been forceful when he brings up the food? Or is it quite passive without any retching or warning?
What is he bringing up in his vomit?
Any changes to his drinking?
What tests and treatments has his vet tried?
Are his gums nice and pink (not white/pale)? Moist or sticky?
If you press on his belly, does he have any tensing, tenderness, discomfort, or pain?
Could he have eaten anything he should not have (ie bones, toys, plants, chemicals, human meds, etc)?
What did the diarrhea look like?