He was pronounced dead at 7:17 am at the Phra Mongkut Klao Hospital. He has been admitted to the hospital on April 4.
A royally-sponsored bathing rite will be held at Wat Soammanas at 3 pm on Friday. Praying rites will be held at the temple from Friday to June 16.
Trairong served as a security advisor for former prime minister Thaksin Shinawatras.
He used to hold several key military posts, including the chief of staff for the Supreme Command and a specialist for the Army.