This problem should not be a problem. Why is the buyer delaying the sale due to this? Is something else going on, like the wall is falling down?
As a general rule, if the retaining wall is on your husband's property, then it belongs to him, and if it is on the neighbor's land, then it belongs to the neighbor. There may be something in the deeds or an easement that changes this.
You really need a good lawyer to guide you in this. The buyer should not be delaying sale due to this. A survey and a review of the title search should be enough information for an attorney to give you some advice. I could do that very quickly for you, and you could then know how to proceed.
Give me a call, make an appointment to come see me, and let's get moving on this for you.
There is NO COST to you for the telephone call, or for the first meeting at my office.
Robert Davies, Esq. 201-820-3460
My contact information can be obtained from the links below, just click on the Attorney Profile link. Let my secretary know you found me through LawGuru.
Please keep in mind that my response is just a general comment on your question, and not legal advice. Your question and any response does NOT create an attorney-client relationship between you and this law firm. The exact details of your situation and things that you have not mentioned in your question can completely change the response I gave. You can not rely upon what I have written, because I do not have all of the information that I need to advise you, I only have the very small amount of information that you put into your question. To get legal advice that you can rely on and use, please contact me directly. I would be happy to assist you.