If a lawyer is hired to draw up amendments to a Trust and the court later finds them invalid, is this malpractice for the lawyer

My parents both had separate irrevocable trusts. My mother was incapacitated for the last 8 years of her life. My father had a lawyer draw up amendments to my mother's trust, which included distributions to beneficiaries. My dad died in 2010, my mother in 2011, at which time distributions were made. Now, after a long suit by one of the beneficiaries, a judge has found the amendments invalid and has ordered beneficiaries to pay back to trust money they received 4 years ago. Since my father paid the lawyer to advise and make the amendments, is the trust lawyer responsible for the amendments not being legal? Malpractice suit? Beneficiaries have already spent the money given to them? Appeal?