Brooke was riding Orchestrated for her mother, Lady Susan Brooke, when falling at the third fence in the Pontispool Equine Sports Centre Handicap Chase on April 8.
Racing was delayed by more than hour as she was treated on track, before being transferred into an air ambulance.
A statement issued by the IJF on Friday said Brooke was in a “critical, but stable condition” in intensive care at Southmead Hospital in Bristol, and had been placed in an induced coma due to “various complications” during the week.
However, a further statement released on Monday confirmed she had died.
The statement read: “It is with deep sadness that we have to share the tragic news that Lorna Brooke passed away yesterday.
“Her family thank everyone for their kindness in the last few weeks, particularly the staff at Southmead Hospital who were so professional.
“They will be having a private funeral and will hold a celebration of Lorna’s life once Covid restrictions allow.”
Sir Anthony McCoy was among the leading racing figures to pay tribute, writing on Twitter: “Heartbreakingly sad news. Thoughts and prayers with her family. RIP Lorna.”
Brooke, 37, who rode as a 7lb-claiming amateur, enjoyed a high-profile success when winning the inaugural Ladies Handicap Chase at Fairyhouse on Moonlone Lane for Paul Stafford in 2015.
A 25/1 chance, Moonlone Lane had gone winless in a 26-race career up to that point, but Brooke guided him home in front, with Katie Walsh, Lizzie Kelly, Rachael Blackmore and Nina Carberry all trailing in her wake. Moonlone Lane then won next time out at Musselburgh under Brooke.
“It’s tragic news, it really is shocking,” Stafford told Sky Sports Racing.
“When she got the fall people were very concerned, we were too and we were saying prayers, but unfortunately this has happened.
“She was a lovely person, obviously she rode that winner for us and we kept in contact over the years through social media, congratulating each other on social media when each of us had winners. It’s shocking it’s happened.”
Thinking back to the day at Fairyhouse, Stafford said: “He’d never won a race until she rode him that day, she took the bull by the horns, went on and it paid off – she gave him a fantastic ride.
“I’d never met Lorna before that, she was more or less allocated the ride, but I knew she was a capable rider. It worked out and she rode him several times again, winning at Musselburgh.
“She was over the moon that day at Fairyhouse, and her family. I met her mother at Bangor one day and she’s lovely too.
“I send my condolences to her family, my heart goes out to them.”