“The parents can always say “no”,…”
I would imagine there is the fear of not being allowed to see the grandchildren if they say no, among other things.
So you are talking about someone who would blackmail their own parents for money, with the threat of withholding visitation or dis-owning the parents.
Why bring learning or Kollel (vs. any other material want, such as a car, house, weed, etc.) into the picture?