FreeRealms Cannot Run on DSi Browser — Hardware Too Limited

No. FreeRealms (shut down 2014) required Flash Player and 3D hardware acceleration. The DSi browser:

• Does not support Flash.
• Has extremely limited RAM/CPU (16 MB RAM, 133 MHz ARM9).
• Cannot render 3D graphics.

FreeRealms was PC/Mac only (later PS3). For browser MMOs today, try RuneScape (HTML5 client) or AdventureQuest Worlds on a computer.