Hi,
Wow, that would be quite complex actually. Delphi uses the Pascal programming language and the VCL library, while making GUI for Raspberry Pi typically involves C++ and the Qt library, that are completely different.
You would essentially need to develop the Raspberry Pi version from scratch and use the Delphi version as your reference. If you don’t have software development experience to do this yourself, we could offer you our consulting services to have this done for you. You can simply contact sales@sysprogs.com with a brief overview of your application so that we could get you a basic estimate.