
Quoting
llworking
If they stay married, your mother will basically get her SS Benefits bumped up to what his was before he died if his benefits are higher. If they are divorced, she would only be able to get a benefit of 50% of what his benefit was. So unless her current benefit is less than 50% of his current benefit it wouldn't do her any good.
There may be other factors in their situation that would make divorce problematic for one or the other of them. Therefore, unless one of them wants to remarry, or if one of them wants the marital assets fairly divided, or there is some other specific reason out there why a divorce would be needed, there may not be much point in divorce at their age