overfunded

Also of note the plan is overfunded by a low 7 figure sum.

I understand this can be a complex matter and I will be seeking professional advice from an ERISA attorney, but i'm trying to develop a basic understanding of the relevant issues so that professional fees can be put towards developing and executing a plan instead of educating me. My father had a business which has not been active since the 1980s. They established a defined benefit plan in 1984 and it was frozen in 1985. The plan has 2 participants. My mother and father. They both made contributions to the plan. My father recently passed away(2017). The plan is overfunded by ~800%. The plan assets are cash and liquid securities. The company has no assets other than the overfunded pension. My father was trustee of the plan. The stock is 100% owned by my fathers estate which I am representative. The massively overfunded pension is not the ideal instrument for my mother's retirement. Can anyone direct me to online resources that provide a good overview of various termination excise tax mitigation strategies and the related issues. I want to be informed when I contact the plan administrator and retain an advisor.