A really simple query?

you can work a limited amount of hours whilst in receipt of DLA (up to 16 i believe), so he can still claim JSA. i am surprised though, as JSA is worked out depending on the income, and if they are not entitled to Income Support, it is more than likely that this is due to them not having a low enough income to be eligible, therefore, from my experiences, i would say that they receive too much to be in reciept of JSA allowance anyway? but contact the job centre to confirm that they are receiving the correct benefits, they may even be entitled to more if they both claim DLA, such as council tax and housing benefit.