The band shared a joint statement one day after the star died in Buenos Aires, Argentina.
The late star attended St Peter's Collegiate Academy before finding fame on X Factor.
The news has also ignited an outpouring of shocked messages from fans.
Tommy died one day after the 21st anniversary of his older brother's passing.
No further details about the nature of Patricia and Alison's deaths have been made public.
The businessman propelled the careers of Reykon and Blessd, to name a few.
The Grammy-winning American Idol finalist was 47 years old when she was found dead on April 18.
The musician was the last surviving artist to chart in the top 10 of the inaugural Hot 100 in 1958.
The country singer, who was on Team Blake and finished as the Voice season 12 runner-up in 2017, shared the news of Janis Duski's death on Instagram.
Known for hits like "Los globos del cielo," the artist stopped performing 10 years ago due to his illness.
