All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
The children of that man should treat him kindly and gently advise him. They should meet his negligence of their rights – as they claim – in the best way, urge him to do good deeds and warn him of evil. They should do so with wisdom and good admonition. To do so, they should pursue all the possible ways such as direct conversation with him, giving him a recorded lesson on this subject as a gift, or asking wise and knowledgeable people to advise him.
What he must do is pay the obligatory rights upon him in his money such as Zakah and financial maintenance of his wife and children who have not reached the age of puberty if they do not have money. If he does not provide for them, then he is committing a sin. It is permissible for his wife to take from his property without his permission to the extent that suffices her and her young children. His adult children, who are able to gain their livelihood, have no right in his money. Rather, each one of them should gain his livelihood to support himself and his children if he has any.
The Muslim ruler should take Zakah from his money and oblige him to pay it. Other people have no right to do so and have no right to interdict him from using his property. Rather, their obligation is confined in urging him to do whatever is made obligatory upon him by Allaah. If he responds to them, this would be fine. Otherwise, they are discharged of their obligation.
Allaah Knows best.