Is it permissible to complete the design of a website for a Sufi sheikh after discovering its content to be misguidance, or is it obligatory to stop working and return the money that was received?

It is impermissible to work for a website that relies on innovation (bid‘ah) and misguidance (dalalah), and it is unlawful to take payment for such work. This is because when Allah prohibits something, He also prohibits its price. Therefore, the website design that has been completed must be retained, and the individual must not be enabled to use it to spread falsehood. The money taken from him should be returned, and he should be advised.