Is the father obligated to help his son with the costs of treating retinal detachment, especially if the father was previously the cause of his son's eye damage? And does this obligation cease if the son curses his father out of anger due to his delay in providing treatment? And is it permissible for the son to secretly take money from his father if the treatment is necessary and the father delays in providing it?

Our advice to you is to seek the reason why your father treats you in that manner, and to apologize to him if you have wronged him, and to clarify matters to him if you have misunderstood him. You should also seek help from those close to him and frequently supplicate to Allah to mend what is between you, for the hearts of people are in the hand of Allah, turning them as He wills. If you are unable to earn a living, then your maintenance is obligatory upon your father. If he withholds it, then it is permissible for you to take from his wealth without his knowledge, to the extent of your maintenance. However, it is better to seek the help of your mother or others to persuade him to provide for you. If the harm to your eye was caused by him, then blood money (diyah) is obligatory upon him. You must be respectful towards him and not mistreat him, no matter how much he mistreats you. You must also repent from any anger or insults that may have emanated from you towards him, for that is a great act of disobedience. You can also seek assistance from charitable organizations to cover the expenses of your treatment.