Connecting from home to Parallels RAS server published applications

I have a customer would like to access the published applications from home. From local network, it works very well.
I suggested to him to access them using company’s public IP by doing port forwarding 80 and 443 for HTML5. Is that correct?
But also he needs to access them using parallels client application. So what are the ports to open and to forward in the firewall?
Please advise regarding the best procedure to access the published applications from home.
PS: the customer doesn’t want to use vpn connection.