Both IB-JSA and HB are two of the six income based benefits that under the Welfare Reform laws, are being replaced by a one payment called Universal Credit. He might already be on UC, or will likely be transferred to UC if he needs to ask for help with his rent. He will better off on Universal Credit than the benefits it is replacing.e.g. UC does not have the sudden end of benefits that the present income based benefits have and when he finds work UC will continue to taper the benefit payment until you are back on your feet: UC allows for debt repayment, whereas the benefits it is replacing do not. It's always best to ask the CAB to do a benefit check to see what he will be better off claiming.
If you have debt and are finding it hard to meet the repayments, don't be afraid to ask for help. StepChange is a government backed debt charity that gives free advice and help (don't pay one of the many companies that are springing up, who want money to help).
https://www.stepchange.org/It's a bit late atm, but when he gets another job, he might want to look at taking out insurance that will kick in if he loses his job, gets too ill to work etc. Look on it like a fire insurance policy, it's needed but you hope you never have to claim on it. Benefits are only a backstop for those in real need and as you can see, they are just survival rates with very little for those that don't have children: although the able bodied parents choosing to live off the benefits intended for their children, are being stopped.