These Are The Symptoms At The Times Of These Sickening

These are the symptoms at the times of these sickening episodes, he gets a weak feeling that starts at his feet and goes up to his head. Then there are goosebumps over his body. It lasts for a couple of minutes until the feeling goes away. At the same time, there is extensive saliva that comes up in his mouth. Enough that it needs to be spit out. He had dealt with this in the pass year, now the episodes are coming back. He may have six to seven a day. What would cause this?