In Indian and Asian culture in general you will take care of your parents just as they have taken care of you when you were a child. Old age is just like childhood age where you have to look after them just as much as you would look after a young child. Having your parents move in with your family is an option so that they don't feel lonely. They can also see their grand children and not feeling lonely at home. Loneliness is one of the main reasons to loose hope in life if they do not have good neighbors or support system. Once hope is lost then motivation to live long also goes away.
Not sure what other think of my opinion but I am living with at my parents at their home currently and just bought a new place and moving with my parents and wife/kids. There is attachment to the home we lived in for this long but we are looking forward to better life in new home together. There can be small disputes living together that may urge you to live separately but I feel if you look past them you all will feel stronger as you all know there is someone in the house to look out for each other.