No, the static route is applied to the OpenVPN traffic as well.
But the providers router may not have a route for the OpenVPN tunnel network. So I guess, its default route is not passing pfSense?
If that's the case, you either have to add a route for the tunnel network to it, pointing to pfSense or do NAT on pfSense for traffic the the network behind the router.
Another reason may be that access from the VPN tunnel is blocked. This can also be circumvented by NAT.