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Radio-loud active galactic nuclei (RLAGN) are the most luminous radio sources in the Universe comma and RLAGN at high-z are important for studying the formation of massive galaxies and supermassive black holes (SMBHs). The discovery of a radio galaxy at z=5.72 (TGSS J1530+1049) has pushed studies of RLAGN closer to the epoch of reionization (EoR). HST imaging of other high-z radio galaxies has shown that such systems are massive comma with intense star-formation. They exhibit complex morphologies comma large sizes and are frequently surrounded by overdensities of faint galaxies comma indicative of a forming cluster environment. TGSS J1530+1049 at z=5.72 offers an opportunity to now investigate these phenomena at zvirgul6 comma and we propose deep multi-band HST imaging with ACS and WFC3 to image the radio galaxy and its close companions comma searching for overdensities on scales of 5 Mpc (co-moving) in its environment. TGSS J1530+1049 is a JWST NIRCam GTO target and is the subject of an approved Cycle 1 NIRSpec-IFU program. It benefits from high-resolution VLBI radio imaging of its AGN jets and is an approved Chandra target. The combination of these proposed HST observations with JWST data will result in maps of the distribution of stellar mass and measurements of star-formation rate comma dust comma ionisation state and metallicity of the gas. Correlating the rest-UV morphology with AGN jets and constraining the evolutionary stage of the stellar populations are crucial to understand AGN feedback in massive galaxies near the EoR. Further comma rest-frame UV HST imaging will allow the identification of any nearby companions through Lyman break selection comma which will not be possible from the NIRCam data alone.