Every parents joy is to have a child who will take care of them at old age, and likewise every child's dream is also how to set a befitting place where his/her parents could be able to live comfortable lifestyle, knowing fully well that training a child is never an easy task, which is why for me I will always say that for those who after becoming successful in life and yet you are still opportune to have your both parents alive, you better take good care of them, because its not all of us who before we made it still had our both parents still alive to enjoy the fruits of their labour.
It is an obligation for every child who has been successful to be able to take care of his parents without having to first tell his parents to take care of him and what we have given to our parents after we have been successful is not enough for what they have given us at that time. We are still children, they have raised us with the love they have given us and we should be able to take care of them when they are old.
You are right, not every child has the opportunity to be able to take care of their parents when they have achieved success, there are even some people who are late in achieving success and their parents have died, so for everyone who still has parents they must be able to take care of them as they are. look after him when he was little.