I don't even know what A... & L... means... Either your husband is 1) lying to you, 2) he's telling the truth and a-it's a mistake by them or b-it's a mistake by you and you owe the money, 3) this is a scam to get money from you.
A validation letter, in my opinion, is the best way to go. The attached link is to the first validaiton letter google showed me. Remember I am not licensed to practice in MI and other rules may apply. If this is helpful, please click the box!
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here. Please visit my web site: www.avanesianlaw.com for more information about my services.
It's hard to give you a sufficient answer based on the information you have given.
Here's the best I can give you: "A&I" may be collection firm for the creditor to which your husband does owe money. There is no requirement that they provide him with an itemization of what the debt is. Your husband has the right to contact them and ask what the underlying debt is.
Be very careful any time you talk or write to a creditor so that you do not waive any of your rights. I highly recommend consulting with an attorney if the amount claimed is significant.