New Breakout Seizures after 15 years? why?

Hey folks!

My boyfriend is 28 years old and had his first seizure when he was 13. His diagnosis was a combined partial seizure and mild stroke - both at the same time. He also remembers having one "aura" before this event when he was 12 but had had nothing before that (no seizures when he was a child). After this first seizure, he had various MRI's, angiograms, cat scans, EKGs, EEGs, etc., as well which showed odd electrical activity on the right side of his brain, as well as white matter on the top of his brain.

Anyway, since that event, he's been on various drugs like Dilatin, Phenobarbital, Tegretol, and Tegretol XR.  Most of his youth, he had occasional auras, but never a seizure since his initial one back when he was 13.  He has had only auras and migraines. (Not sure if the meds he was on prevented seizures or not). Throughout college he drank and stayed up late, everything that you could imagine would be a seizure trigger he did and still he had no seizures - just auras occasionally. 

He has been on Trileptal for the past several years, 1800 mgs.  He tried the generic  for a few months last year bc the cost was so much less than the brand, and he had his first set of break-through seizures while on the generic - after just 3 months of being on it. So he immediately switched back to the brand trileptal and had another seizure in Dec last year. I forgot to mention he has Complex Partial seizures, and his recent seizures have all been both generalized tonic-clonic and, after that one is over, back to complex partial til it's all over. So then he was placed on 2100 mgs of Trileptal, and he had another break through seizure in Jan of this year. So now the Dr. has him on 2100 mgs of Trileptal and 2000 mgs of Keppra XR in hopes of weaning him off of Trileptal.

I think it may be a possibility that the drug simply wore off but I have been doing some reaserach on food triggered seizures and Soy and Gluten were brought to my attnetion. My boyfriend starting drinking soy milk around the time of his first breakthrough seizure. I told him to stop drinking it after his last seizure and his headaches stopped which was a good sign. Celiac was a thought but his blood test came back negative so i think we might go to an allergist.

Basically my question is: Has anyone had the same experiences or any info on Soy triggereing seizures in people with epilepsy? 

He never had a seizure immediately after drinking soy milk so im not sure if that has anything to do with it. Any info would be much appreciated!

Thanks!!