I have a question about the legalities of using the Entrepreneur Visa:

A person (Non european)is in the UK on a sponsored visa through a company (company a), during this sponsorship he opens up his own limited company (company b) but is still paid a salary from company (a).
Company (a) closed down so he didnt have a visa in the UK, so he applied for an Entrepreneur Visa for his wife (who is an american) and opened up another company (c), and now holds a visa based on his wife having an Entrepreneur Visa and him being her husband.

If he is still the director of company (b) and claiming a salary form company (b) - is his and his wife's Entrepreneur Visa a valid one? and is he legal to live,work and employ people in the UK?

Thank you.