Most lawsuits are filed by buyers.
Your Realtor should have had insisted that work be completed by professionals. Once a property is listed, I insist that a licensed, bonded repair be made, then show the receipts to the buyer. The disadvantage to waiting until your home is in escrow to do repairs is that if your husband did them, and for someone reason the buyer is not happy, you open yourself up to questions.
When a professional does the job, that professional is on the hook for the dissatisfaction and needs to correct the work to the buyer's satisfaction.
So part of escrow process is having the buyer request repairs be made, in writing. Did that happen?
When you say "having problems', do the problems relate to the list of repairs?
Did the buyer's agent and buyers do a walkthrough a day or two before closing to review the repairs?
You don't give details on the repairs, but if they were made, then is it the quality of workmanship, or did the repairs not fix the problems?
You may need an attorney. I am not an attorney. I would suggest reviewing your concerns with your Realtor and if necessary the Realtor's broker. Try to resolve it directly first.