Right or Wrong

I have unexplainable gratitude towards my parents for the selfless sacrifices they made during the course of life while raising us. I don't know even a single instance where they were selfish to do something for themselves keeping us aside. In this process they totally got lost in serving us and others and didn't develop any interest that can keep them happy. After my brother, my sister and myself moved out of house for higher studies and jobs, they still seem to be continuing the same life style. We siblings severely failed in convincing them to travel or go around and have some good time. As far I know, mom and dad are not much inclined towards traveling. They know most of the things that could make us happy but unfortunately we don't know even a single thing that could make them happy besides us staying happy making them happy which is again for us but not for themselves. There were times I argued with them to convince them stop worrying about saving for us and to focus on their retirement life and to have a good time with no worries. And everytime I discussed such topics I sensed that they were left with hurt feelings. Not sure if it is right or wrong to argue with them while stressing on how important it is for mom and dad to think of themselves for their wellbeing. I seriously wish mom and dad have a peaceful and happy life going forward and do things for their inner well being.   I am definitely not talking about materialistic things here, it's things that will make their inner soul happy and calm. If it is the materialistic things that will make them happy, then certainly I wish they discuss with us so that we can do our best to fulfill them for them.