does he have headaches with the vomiting and dizziness?
Get him to a hospital! It could be anything, but it could be cancer, and cancer if detected early can be treated with a little surgery and a few weeks of chemo! but if you keep it up, it could be a cyst that has popped and he might need antibiotics, regardless, hes probably going to need some kind of medication, please get him checked, im 16, i went to the doctors today and had him look at my testis, now more people are going to look at them, and after that its possible more people MIGHT look at them.... thats hard to do, he just needs a checkup, not people messing with his junk like me, and let me know how it goes okay?
I dont know what to tell you my advice would be to see a doctor as soon as possible while it is early