If you have been giving honest feedback about the performance issue and he is aware of what is going on, you can risk a termination whitout compensation but you are probably getting sued. If he is not aware about the management insatisfaction you are most likely getting sued because he will see receive it as an unjust termination.

The best case scenario here is to push some form of compensation agreement.

Also, as a manager, you should build trust, even you people that you don't particularly like, so termination without compensation can have negative lasting effects on teammates.