What is the ruling on the heirs of a worker taking money from the institution where he used to work in exchange for signing documents agreeing to that?

The questioner did not clarify the conditions and terms of the documents requested from her father, and therefore it is difficult to rule on the permissibility of this action. If she means solidarity funds, some of them are permissible and some are forbidden. If what is meant is a grant given to the heirs of a worker after his death, then there is no objection to taking it and signing for it.