Praise be to Allah.
The Prophet (peace and blessings of Allaah be upon him) forbade wasting money and spending it on things that are of no benefit.
It was narrated that al-Mugheerah ibn Shu’bah (may Allaah be pleased with him) said: I heard the Prophet (peace and blessings of Allaah be upon him) say: “Allaah dislikes three things for you: gossip, wasting money and asking too much.” Narrated by al-Bukhaari (1407) and Muslim (593).
The scholars regarded bad handling of wealth to be a kind of mischief (fasaad). Imam al-Bukhaari named a chapter on this basis as he said: Chapter: What is forbidden of wasting money and the words of Allaah, may He be glorified and exalted: “and Allaah likes not mischief” [al-Baqarah 2:205].
Fath al-Baari (5/68).
A person may be clever but he does not handle money well, rather he wastes it and spends it on things that are of no benefit. Such a person is described by the scholars as safeeh (foolish), and it is not permissible to give him money, rather he should be prevented from handling it, because Allaah says (interpretation of the meaning):
“And give not unto the foolish your property which Allaah has made a means of support for you”
al-Qurtubi (may Allaah have mercy on him) said: This verse indicates that it is permissible to withhold wealth from the one who is foolish, because Allaah enjoins that in the words “And give not unto the foolish your property” and He says: “But if the debtor is of poor understanding [safeeh], or weak” [al-Baqarah 2:282]. So a guardian is to be appointed for the foolish one just as for the weak one. The word “weak” applies to a minor whereas the word “foolish” applies to an adult. End quote.
Tafseer al-Qurtubi (5/30).
Ibn Hajar (may Allaah have mercy on him) said:
With regard to the words of Allaah “And give not unto the foolish your property…”, al-Tabari said, after quoting the views of the mufassireen on what was meant by al-sufaha’ (the foolish): The correct view in our opinion is that it is general in meaning and applies to everyone who is foolish, whether he is a minor or an adult, male or female. The foolish one is the one who wastes wealth and mishandles it. End quote.
He also said:
Withholding in sharee’ah means preventing him from disposing of the wealth, which is sometimes in the interests of the person and sometimes in the interests of the wealth. The majority of scholars are of the view that it is permissible to prevent an adult from disposing of wealth (in such cases). End quote.
Fath al-Baari (5/68).
If your father does not handle money well, rather he wastes it on things that are of no benefit, then he must be prevented from handling it and it is not permissible to give him control of any wealth. Your mother should cancel the power of attorney or control that she gave to him, so as to protect your property from being lost, because you need it.
You have to advise him and bring him back to his senses by reminding him with kind words and exhortation that will make him regret what he has lost of his wealth, and make him be careful with what he has left.
Remind him of the ahaadeeth which will rebuke him for wasting money, and remind him that Allaah has entrusted him with taking care of you, as it says in the hadeeth of the Prophet (peace and blessings of Allaah be upon him): “It is sufficient sin for a man to neglect those for whom he is responsible.” Narrated by Abu Dawood (1692) and classed as hasan by al-Albaani in Saheeh al-Targheeb (1965).
Shaykh ‘Abd al-‘Azeem Abaadi (may Allaah have mercy on him) said:
Al-Khattaabi said: This means the ones for whom he is obliged to provide food, meaning that the one who wants to give in charity should not give in charity if he does not have anything surplus to the needs of those whom he is responsible to feed, seeking reward thereby, lest that incur sin for neglecting those for whom he is responsible instead of earning reward.
‘Awn al-Ma’bood (5/76).
If this applies in the case of one who is giving charity, then what about the one who wastes money on things that are of no benefit?
And Allaah knows best.