First of all let me wish all the best to your son, I have a daughter at the same age, and I hate to see my children suffer. I cannot tell you what to do, but I can tell you my experience with a partial obstruction I had last year. I was in a lot of pain, it was like I was giving birth again, and I was vomitting a lot. I too had 2 bm's that same morning, that's why it was only a partial obstruction. When I went to the ER they did some blood tests and my WBC and CRP was very high, and I was running a low grade fever, that's why they admitted me immediately. The obstruction cleared after 10 days of IV antibiotics and high dosages of prednisone, and of course clear liquid diet. My main worry would be if he was in a lot of pain or vomitting. My disease is also located in the terminal ileum.
In case he had a total blockage, he would not be able to pass gas or have a bm.
The problem is that your son is still a child, so you have to decide what the next step will be. If it was one of my daughters, and I didn't see an improvement, I would drive them to the hospital, just to be on the safe side.
Hopes he feels better soon,