I've had migraines since I was tiny - horrible at school, as no-one seems to understand. I've been on strong medication for them but am not able to currently as I'm breastfeeding, but have found a few things that help. Ibuprofen seems to work for me better than paracetamol, but whatever it is needs to be taken right at the start of an attack. I used to be embarrassed about asking to go out of the classroom at school to take medicine as soon as I started feeling a migraine come on, but that did really make a difference. Does your son feel a migraine coming on before the headache starts?
Another thing that works for me and helps the nausea is a can of cold coca cola drunk with the ibuprofen - no idea why this works, something to do with the sugar and caffeine? - but could be worth a try.
I've tried lots of strong medication, and although things like triptans can feel like a miracle cure during an attack, I did get side effects from them and ended up taking them more and more as I was getting rebound headaches. When I stop breastfeeding I think I'll only use them again with great caution.
And like others have said, just keep working on identifying triggers. I don't really have food triggers, my main ones are going too long between meals, not drinking enough, waiting too long to go to the loo (weird I know!), getting too hot and fluorescent lights (especially flickering ones).