John Brown's skeletal remains were found by firefighters called to Alistair Brown's flat in December 2010 after a water pipe burst in freezing conditions in Denny, Stirlingshire.
Alloa Sheriff Court heard that Brown, 61, who acted as John's carer until his death at the age of 69, hid the corpse after he died from natural causes in August 2007.
But he failed to inform local council officials, and subsequently claimed £38,237 of benefits paid into his brother's bank account.
Brown, now of Falkirk, pled guilty to the fraudulent scheme at a pre-trial review.
Sheriff Kenneth McGowan deferred sentence until next month for reports