[dottiesyrky]

Thank you for clarifying your question.
First I am sorry your baby is having these issues. Vomiting foam and bile can often be due to an empty stomach. My boy used to do this early in the morning after a long fast. I solved this by feeding him a light meal before he goes to bed. Also my vet suggested Pepcid at night. These two solutions seem to have cured the issue. Also feeding more frequent smaller meals may suit him better.
Also the dog may have gastric reflux that has many causes. I have found that if my dog is stressed, sometimes he tends to throw up bile and foam. But usually he will eat and be ok afterwards. If he is really sick he will not eat.
Of course you might get your dog seen and tested by the vet in case he has some underlying issue such as pancreatitis. Some dogs are very sensitive to rich food, people food, or treats that can upset them. My dog had one minor bout of pancreatitis and ever since I have fed him only Hills Prescription ID Low Fat kibble or canned food and either no treats or very low fat treats. Since then he has been fine. So really I would suggest a vet visit to rule out any health reason, and also note when and what he throws up and what happened beforehand to see if there is a pattern. But of course probably your dog is fine and just gets something that his tummy does not like now and again. Good luck, and please let us know how he is doing.