As much as you feel that this person deserves a comeback (and I feel the same by your description), that's not about it. The team will question and distrust the company, you will give enough fuel for grapevine conversations that already happen (they have signal/whatsapp/discord groups where this is an active subject). I'd pay out, let this person go and never talk about them again. This way when they come back or keep saying bad things about the company there will be more people to remind them that everything is on the table except honoring agreements, which they didn't do btw. It is hard being a human tho, we always want to drop the lightning bolt on what we perceive as unfairness but it is a person against a company. Let it go.