The only poor response noted is his vomiting and nausea. Since he just started his second round of chemo on Wed. and the stroy came out on Friday, it is too early to determine how the cancer itself is responding. Chemo isn't fairy dust. You don't take one dose and notice an effect on the disease process. If he was taking antibiotics for a bacterial infection, you wouldn't notice a difference in the disease process after a mere 48 hours, either. But you might get nausea and vomiting from taking them, which means you are not tolerating them as well as someone that doesn't have nausea and vomiting. It in no way means that they are not effective for the disease being treated.
However, due to the fact that since February, the cancer has worsened and the tumor has increased in size means that, even after an extended period of time, herbal treatments were not working. And you also need to keep in mind that his mother said he is "responding poorly", just because he is vomiting. That is hardly a medical assessment as to whether the cancer is responding to treatment.