I can't comment on this particular vehicle, but to remove the figure you would first have to inspect the figure to see if he is cast with the seat, or added onto the seat.
As the vehicle is resin (polystone?) and the figures are metal, the driver may be separate. If he is you will be able to see that and then I would work him loos by 'gentle pressure' of a craft knife blade to break the glue join.
If the seat is part of the figure, then the whole seat, with figure, would come out, and the only way to fix that is make another seat.
I hope that helps, but let me know about the driver/seat and even send images?
John