The Muslim man who disarmed one of the shooters, was shot five times after disarming the shooter, but I have not found out who shot him.
..Best we have so far..Update;
Australian authorities reveal Bondi Beach terrorist Naveed Akram, was ‘Australian-born’; previously under investigation for terrorist links.
The terrorist who carried out the massacre alongside his father was under investigation 6 years ago over terror links and extremism- but was cleared after a 6 month investigation in 2019 by the Australian Security Intelligence Organisation.
His father Sajid Akram, who also carried out the attack, arrived in Australia on a student visa in 1998 and then transferred in 2001 to a partner visa and had since been on resident return visas.
Source: Sky News Australia, The Guardian