Definitely just fire him and be open about why with the rest of your team.
If you are really worried about the rest of your team, just discuss it with them first and ask them for advice on what you would do, most of the time if he's really slacking they will wonder why the guy is still in the company.
The other option is to just fire him and then explain that you've been given feedback to him for a while and that you've had enough and that letting him vest would just be plain unfair to people who do put in the work.
Depending on the size of his grant, your current and future investors will think you are weak for letting him vest. That's also a conversation you don't want to have.
The other option is to just fire him and then explain that you've been given feedback to him for a while and that you've had enough and that letting him vest would just be plain unfair to people who do put in the work.
Depending on the size of his grant, your current and future investors will think you are weak for letting him vest. That's also a conversation you don't want to have.