Is the agreement to take turns caring for the sick father between the only son and six daughters a fair agreement? Should the son serve him two days a week, similar to the inheritance? Does the in-laws' refusal to send their wives to serve their father affect the obligation of service falling solely on the son? Should the father's statement be rebutted? Is it permissible for the son to waive his inheritance?

Our advice is to utilize your father's old age by showing him dutifulness and obedience, seeking thereby the countenance of Allah the Almighty.

A summary of the answer to your question:

1. Serving parents when they are in need and are unable to care for themselves is obligatory upon children, both male and female, either by performing the service themselves or by hiring someone to do it. 2. Agreeing to alternate in providing service is sound and just. Serving parents is considered part of the obligatory expenditure when they are unable to provide for themselves. Jurists differ on how this expenditure should be distributed among the children: whether equally, according to inheritance shares, or according to financial capability. 3. The husband's right over his wife is more emphasized than the father's right. If your sisters' husbands permit them to provide service, then so be it. If they do not permit it, then they (your sisters) must hire a servant or contribute to the servant's wages. Neither they nor their husbands have any favor over you in this regard. The service is not incumbent upon you alone; the husbands' refusal does not absolve their wives of the right to hire someone to undertake their share of the service. 4. You must repent and feel remorse for your harsh reply to your father, and not return to such behavior. 5. Your renunciation of your inheritance right before your father's death, out of anger towards him, is not valid and is not binding upon you.