Am I sinful and do I bear the burden of what my former partner does in terms of unlawful commercial activity (selling embroidered and unembroidered abayas), after 9 years have passed since the dissolution of the partnership and 4 years since his retirement, with the commercial register, workers, and bank accounts remaining active in my name? And how should I deal with him?

If embroidered abayas are an adornment in themselves and are used for display outside the home, then it is not permissible to make or sell them. Otherwise, there is no harm in selling them, except to someone known to be using them for display. If your friend sells items that are impermissible and does not respond to your advice, then there is no sin upon you, because you are not his partner and you have advised him. However, if the retention of your name helps him in his work, then you must strive to remove and cancel it through legal means.