my mom has invested in her job stocks longterm IncentivePlan N passed withNo power of attorney N my DadnMom been Separated for20yrs N he lives N anoth

You have to see what time of plan is involved.  Depending on this, you might have to go to court, or might be able to deal directly with the employer.  As to your father's involvement, was he listed as a beneficiary on the plan if your mother were to pass?  Even if not, a question is whether he is entitled to anything since he may have been living with her when she earned the money.  Were they legally separarted?