[Nord20]

Don't forget that just because he is a shareholder doesn't mean he has an automatic right to be a Director (or employee). Hold a vote of no confidence in his abilities to add value to the company and fire him as a Director - you can't take away his shares though, unless you can convince him to sell.

Your first and only duty is to the welfare of your company.

[ry0ohki]

Typically (hopefully!) shares are vested based on work as an employee, in which case you can get back the unvested shares at least.