Is working for a company owned and managed by someone who inherited money from the alcohol trade, and still has a share in it, considered unlawful? And is it permissible to continue in this job while searching for an alternative?

If the company owner's funds originate purely from unlawful sources, such as the proceeds from alcohol sales, and there is no lawful money involved, then it is impermissible to work there. However, if his funds are mixed with lawful money, then it is permissible to work for the company, albeit with some reprehensibility (karahah), provided that the company's field of work is permissible. It is not permissible to trade in artifacts and gifts made in the form of living beings, except for children's toys. Work is only permissible if the owner's money is mixed (with lawful funds) and the company's work is permissible; otherwise, it is obligatory to leave the job unless there is a necessity that permits the forbidden.