It depends on what triggers his epilepsy. If he is affected by strobe lighting, for example, then I would say being a DJ is not a great idea. Aside from that, there are very few jobs that would be unsuitable. Just think about
whether there is something that would cause a seizure or make it more likely. If he has seizures a lot and are uncontrolled then I would tell the employer and consider if he would get hurt in the job. For example, in a Pizza House there is a high chance of being burned. The employer would be the best person to advise you in that situation since he will have considered and health and safety risks.
I hope this helps you
Darren