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 wee one’s situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner, but can you tell me:
What is he bringing up in his vomit?
Does he seem weak with wobbliness? Or any reduced leg use, circling, or head tilting?
Are his gums pink or white/pale? Moist or sticky?
If you press on his belly, any tensing, tenderness, discomfort, or pain?
Could he have eaten anything harmful (ie bones, toys, plants, chemicals, human meds, etc)?