It sounds like he is capable of acceptable work for your team but is not performing to his earlier level: do you understand why? What's his side of the story? T

It sounds like he is capable of acceptable work for your team but is not performing to his earlier level: do you understand why? What's his side of the story? The best outcome would be to enable him to continue as a fully contributing member unless there are additional facts that indicate otherwise. Is there someone that both you and he trust that you could use to mediate a serious conversation about how to resolve the situation? The 15% founder should be willing to sell you back 12-14/15's of his stock since a normal vesting period would be four to five years from a standing start. He may not be willing to do so.