So you waited 30-40 years to enforce, it? I believe it would be safe to say the Statute of Limitations has expired.
Legal disclaimer: This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice nor does it constitute an attorney-client relationship. Thank You
There are several issues here. One is whether waiting 30-40 years to enforce a support order would be barred by the Doctrine of Laches. There is no statute of limitations relating to support but something similar, Laches, may prevent enforcement.
And, here is the other question: who is entitled to enforce the support order. The "children" are adults. Some cases hold that the right to enforce a support order for a minor is that of the child once the child reaches their majority. IF your child was disabled with a permanent disability, then the guardian may be able to go forward.
Any determination as to whether too much time has passed will be based upon the particular facts and circumstances. Was an effort made to find the father? If so, was it cursory or was a real effort made? Did the father change his name? Hide? Or, in a place where he could have been found if a dedicated effort was made, such as in the military or in jail? How many times did you attempt to locate him? And so forth.
I hope you found this response to be of assistance. This response shall not be considered the rendering of legal advise but instead a general response to a general question. While Avvo is a wonderful resource, nothing can be a substitute for an in-depth consultation with an attorney in the jurisdiction in which the law is to be applied. This response shall not be deemed to create an attorney-client relationship, nor shall it create an obligation on the part of the attorney to respond to further inquiry from the questioner.