This is the best solution. Shows you’re “extra generous” instead of just letting someone walk with their equity. Shows “the company will take care of me.”
Agree with above points. It sounds like it should have been dealt with a long time ago. Being this close to vesting is the cost of inaction. The equity issue feels like a sunk cost at this point.
Would initiate a conversation around performance to set expectations that performance needs to improve or their position is at risk.
Be the hero of the story: treat the employee fairly and raise performance expectations. Hopefully, the equity is a small price to pay.