The simple answers is YES in normal circumstances.
No matter what the conditions and financial constraints one may have, it is a basic responsibility to look after your parents.
Questions come in case some parents become less loving / abusive towards a particular son / daughter compare to others, in which case one may use their discretional wisdom as how much they can reciprocate lately.
Some parents try to take away money from one son/daughter to other who may not b in financial distress, but just the fact that parents love the other most.
Also historically parents were abusive with their kids and this may translate to grandkids as well. In which case again you have to use discretional wisdom on love and responsibility of your kids vs. parents.