Is he your DD's father? If not how long have you been in a relationship? I would be cautious about moving him in from a relationship POV and not just a financial POV. And if he does move in, the DWP will treat you as a couple expected to support each other financially.
Does he have savings? Debts?
I assume he's renting atm and doesn't have a mortgage or own any property?
He will be entitled to claim contributory JSA (or "new style JSA" under the universal credit system) for up to 6 months while he is looking for work. This is not means tested so any savings or other income will not be considered. It's £73.10/week IIRC.
If he moves in with you, you will have to stop claiming income support and it will affect your other benefits too (child tax credits and housing benefit). You will lose your 25% single person discount for council tax.
If universal credit has been introduced in your area, you will have to make a joint claim for universal credit and this will replace your income support, CTC and HB. You will only be eligible if your combined savings are less than £16k. Savings under £6k are disregarded and any savings between £6k and £16k will reduce the amount of universal credit you get. If and when he finds a new job, he will need to declare his earnings and this will reduce the universal credit award.
Have you discussed how you will split rent, bills and other living costs? Is he willing to support your DD financially? If he gets another job will he pay his share in proportion to his savings (compared to your benefits) or will he expect 50/50 or you to pay more because of your DD?