Xenia (the Xbox 360 emulator) has come a long way, but Forza Horizon 2 is classified as "in-game" (not "playable"). This means:
If you own the original Xbox 360 disc, you can rip it to your PC (MakeMKV/ImageBurn) and run it through Xenia. This is legal in some jurisdictions (Fair Use for backup). However, the performance is still poor. forza horizon 2 pc download exclusive apunkagames
Typically, the listing claims: