Poor Brodie and you. I'm very sorry to hear about all the vomiting Brodie is doing, I so understand how worried you must be. Has your vet mentioned or considered IBD? It's very common in cats and does cause chronic vomiting. I've mentioned this before but I don't know if you looked into it more, it's usually treated with prednisone to control vomiting. I sure hope Brodie starts keeping more of his food down and feels better soon. Big hugs to both of you.