Physically Looking after Parents

Q: Is it necessary for the son or daughter to physically look after his or her parents?

A: If a son or daughter can physically look after their aged parents then this is for more rewarding. If not, the alternative will be to employ a full time nurse whose salary will be shared by all the siblings. Is it not correct and unfair to impose this burden on only one or two children, unless some of them are in extreme financial straits.