is it a good offer?

Since your husband is unemployed, so you should analyze the terms and conditions of the deal before accepting it. Can your husband afford to pay $120 every month? If he can't, then he should negotiate with the card company to lower the amount.

At first, your husband???s need to check whether or not he could afford it. If yes, then he can accept the offer. Otherwise, he may get a secured loan from the financial institutions to repay the existing debts. The interest rate on this loan is lower as compared to the other loans.

As he is unemployed, first he has to think properly and have to analyze whether he is able to pay $120 for four years. If he is not, I think he should contact the credit card company and request for negotiations.

Why are people repeating the same answer?

Ok....48x$120 is $5760. How much does he owe? Are they charging interest? Is this agreement in writing? Who is the creditor?

How old is the debt? Once your state statute of limitations has expired, he has no legal obligation for the debt, and can contest any legal action to collect it based on expiration of the statute of limitations. Also I would advise checking out your state SOL statute to see if entering into such a firm agreement to pay will act to reset the SOL on the debt. In some states, it does. In my opinion, the SOL issues would be the first thing to check out.
What derogs have been reported to the CRAs, and when are they due to expire from his CR due to running of the relevant CR exclusion period? If they have time to run after expiration of his repayment period, you might also want to consider negotiating the deletion of those items from his credit file once payment has been fulfilled.
As has been said, entering into such an agreement can be very helpful, but if he fails to abide by its terms, then it will probably result in immediate action on their part to move to collect the debt in court. So be very sure he can abide by whatever terms he agrees to.