Suggest Treatment For Frequent Vomiting?

My brother, who lives in another state has non stop vomiting. I am alarmed to hear he is still having this. He has had this problem for 1 1/2 years now!!! He was snowboarding and his daughter hit him, knocking him out. He immediately started vomiting. He was hospitalized for a week, multiple tests have been run. Doctors in the area are baffled, can t seem to find the source. I am EXTREMELY concerned! I believe there is a tear or something internal that is being overlooked. Should he get a PET scan or something? I m just trying to think of anything to help get the proper diagnosis. HELP!!!! I work in a surgical unit & will ask the surgeons on Tues what & where we should be looking, but Tues is so far away! Before I pay I want to speak with my brother to make sure I ve got all s/s, plus find out all tests ran. Thank you.