Is it permissible for the children to place their father under guardianship? The righteous children and their mother fear the irresponsible disposal of the father in properties which he jointly owns with his children, but they do not possess a legal document to prove that joint ownership. The father uses this as a point of pressure. It should be known that he enjoys good health and is 65 years old, but he does not fear Allaah in his actions.
May Allaah Reward you.

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 right of parents in Islam is immense. Dutifulness to them is one of the best good deeds and undutifulness to them is one of the grave major sins. Placing the father under guardianship by his children to prevent him from disposing of his property is an act of undutifulness and injustice if he is not foolish or insane. If the father has to pay due debts and his property does not meet these debts, the creditors can demand placing him under guardianship. It is impermissible for the children to place him under guardianship for that reason.

Yes, the children have the right to prevent him from disposing of their own properties if they could. They should give him from their properties according to the extent of his need. If the father denies the property of his children for which there is no evidence, they can take it or what is equal to it without his knowledge or consent, even if in secret or by trickery. This is called the issue of Thafr (victory). The basic ruling in this issue is the Hadeeth of Hind bint ‘Utbah in which the Prophet, sallallaahu ‘alayhi wa sallam, said to her: “Take from his money, according to what is reasonable, what is sufficient for you and your children.” [Al-Bukhari and Muslim] The child and the wife are regarded like others in the issue of Ath-Thafr.

Allaah Knows best.