Praise be to Allah.
Undoubtedly honouring one's parents is one of the greatest acts of worship by means of which a person may draw closer to his Lord. Allaah has enjoined good treatment of them in all circumstances, even if they disbelieve in Allaah. We have already discussed this in questions no. 22782, 5326 and 5053.
With regard to what you have mentioned, try to convince your father to let you do work that you are good at, through which you can produce something good for others, for every one has an affinity with that for which he was created. Part of doing things well and fulfilling the trust is for each person to be placed in a job for which he is suited. Part of failing to work well, wasting money and neglecting the trust is to assign work to those who are not qualified to do it. Then try to help him to find a good and trustworthy alternative, who can help him with his business instead of you, even if you have to pay part of his wages. Do that to please your father. If the situation requires you to spend part of your free time with your father, then do that.
“and do good. Truly, Allaah loves Al-Muhsinoon(the good-doers)”
“and be dutiful and good to parents”
If you try hard to do that, but you do not manage to convince your father, then my advice to you is that you should take a leave of absence from your current job, if possible, and join your father in his work for this period. Perhaps things will go as you wish during this time. If you cannot take this leave of absence, then you do not have to give up your job or pay any of your wealth or divorce your wife in order to please your parents, if that will cause harm to you. Your not obeying them in this case is not regarded as ‘uqooq (the defiant disobedience of parents that is forbidden in Islam), in sha Allah. See question no. 9594 and 47040.
A man said to Imam Ahmad: I have a slave woman and my mother is asking me to sell her.
He said: Are you afraid that your heart will follow her? (i.e., are you afraid that your heart will remain attached to the slave woman if you sell her?). He said: Yes. He said: Do not sell her. He said: But she (my mother) is saying that she will not be pleased with me unless I sell her. He said: If you fear that (selling the slave woman) will affect you, then she (your mother) has no right to make such demands.
Al-Adaab al-Shar’iyyah by Ibn Muflih, 1/448.
But you must also strive to soften your father’s heart and be gentle in your dealing with him. Also try to purify your business from selling things that it is forbidden to sell or that you think are most likely to be used in haraam ways. Do not sell these things even if you father tells you to do so, because there is no obedience to any created being if it involves disobedience towards the Creator.
What you have mentioned about notebooks with pictures on them, this is a problem that is widespread. If these pictures are taken from photographs and are not drawn by hand, then there is no sin in selling these notebooks with these pictures, in sha Allaah, because what is being bought is not the picture in and of itself, but rather the notebook. But if it is a picture of a woman or some indecent image, of which there are many such, then it is not permissible to sell it because that is spreading fitnah and corruption, and because many people look for such pictures.
With regard to selling music books, this is haraam, because it is helping in evil. The same applies to selling shavers to one whom one thinks will most likely use it to shave his beard. But if he is going to use it for some permissible purpose, then it is permissible to sell it.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) was asked:
My father has a store in which he sells electrical appliances such as TVs, VCRs and some musical instruments, as well as gold watches. He asked me to sit in the shop and sell things, but I refused. Is this considered to be defiant disobedience to my father? What should I do?
This is not defiant disobedience, if you refused to do the haraam action that your father does. But what you have to do is to advise him and tell him that this is haraam and his earnings are haraam. If he follows right guidance, then this is what you want. But if he does not follow right guidance, then the sin is on him and you will have the reward for advising him, because Allaah said to His Prophet (peace and blessings of Allaah be upon him) (interpretation of the meaning):
“Not upon you (Muhammad) is their guidance”
If he tells you: Sit in the store and sell things, do not sell anything that will be used for haraam purposes, but sell the things that people usually use for permissible purposes. So do not sell things such as radios, cassette recorders, VCRs and TVs, because most of those who buy these things are going to use them for haraam purposes.
Al-Baab al-Maftooh, 1/192.